--- title: "Fall Greenhouse Prep: What to Do Before the First Frost" description: Get your greenhouse ready for fall. BC Greenhouse Builders shares cleaning, insulation, and heating tips to protect your plants before the first frost. image: https://blog.bcgreenhouses.com/hubfs/Greenhouse%20Interior/BC%20Greenhouses%20Fall%20Sale.jpg --- [Skip to content](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#main-content) Announcement Bar/Update or Announcement   Learn More This is a search field with an auto-suggest feature attached. - There are no suggestions because the search field is empty. [![](https://blog.bcgreenhouses.com/hs-fs/hubfs/bcg-ftr-logo.png?width=253&height=51&name=bcg-ftr-logo.png)](https://www.bcgreenhouses.com/) [![](https://blog.bcgreenhouses.com/hs-fs/hubfs/bcg-ftr-logo.png?width=253&height=51&name=bcg-ftr-logo.png)](https://www.bcgreenhouses.com/) - [Greenhouses](https://www.bcgreenhouses.com/greenhouses/) - [Buying Tips](https://www.bcgreenhouses.com/greenhouse-buying-tips/) - [Instant Pricing](https://www.bcgreenhouses.com/design-your-own/) - [Supply Shop](https://www.bcgreenhouses.com/shop/) - [Greenhouses](https://www.bcgreenhouses.com/greenhouses/) - [Buying Tips](https://www.bcgreenhouses.com/greenhouse-buying-tips/) - [Instant Pricing](https://www.bcgreenhouses.com/design-your-own/) - [Supply Shop](https://www.bcgreenhouses.com/shop/) [Say Hello](https://www.bcgreenhouses.com/resources/easy-quote/) [View Catalog](https://www.bcgreenhouses.com/resources/catalog-request/) # Fall Greenhouse Prep: What to Do Before the First Frost [garden preparation](https://blog.bcgreenhouses.com/tag/garden-preparation), [Fall gardening](https://blog.bcgreenhouses.com/tag/fall-gardening), [fall greenhouse](https://blog.bcgreenhouses.com/tag/fall-greenhouse) ### Search Our Blog This is a search field with an auto-suggest feature attached. ### Browse More Content By Topic Tag/Category - [BC Greenhouse (77)](https://blog.bcgreenhouses.com/tag/bc-greenhouse) - [BC Greenhouses (50)](https://blog.bcgreenhouses.com/tag/bc-greenhouses) - [garden preparation (41)](https://blog.bcgreenhouses.com/tag/garden-preparation) - [backyard greenhouse (37)](https://blog.bcgreenhouses.com/tag/backyard-greenhouse) - [hobby greenhouse kit (31)](https://blog.bcgreenhouses.com/tag/hobby-greenhouse-kit) - [small greenhouse kit (31)](https://blog.bcgreenhouses.com/tag/small-greenhouse-kit) - [greenhouses (29)](https://blog.bcgreenhouses.com/tag/greenhouses) - [greenhouse gardening (27)](https://blog.bcgreenhouses.com/tag/greenhouse-gardening) - [greenhouse tips (27)](https://blog.bcgreenhouses.com/tag/greenhouse-tips) - [seeding (25)](https://blog.bcgreenhouses.com/tag/seeding) - [Winter Garden (23)](https://blog.bcgreenhouses.com/tag/winter-garden) - [attached greenhouse (23)](https://blog.bcgreenhouses.com/tag/attached-greenhouse) - [hobby greenhouse (23)](https://blog.bcgreenhouses.com/tag/hobby-greenhouse) - [garden transition (22)](https://blog.bcgreenhouses.com/tag/garden-transition) - [greenhouse garden (20)](https://blog.bcgreenhouses.com/tag/greenhouse-garden) - [build a greenhouse (19)](https://blog.bcgreenhouses.com/tag/build-a-greenhouse) - [greenhouse (19)](https://blog.bcgreenhouses.com/tag/greenhouse) - [greenhouse garden tips (17)](https://blog.bcgreenhouses.com/tag/greenhouse-garden-tips) - [Summer Garden (16)](https://blog.bcgreenhouses.com/tag/summer-garden) - [growing food (16)](https://blog.bcgreenhouses.com/tag/growing-food) - [winter greenhouse (16)](https://blog.bcgreenhouses.com/tag/winter-greenhouse) - [growing in a greenhouse (15)](https://blog.bcgreenhouses.com/tag/growing-in-a-greenhouse) - [buy greenhouse (13)](https://blog.bcgreenhouses.com/tag/buy-greenhouse) - [Fall gardening (12)](https://blog.bcgreenhouses.com/tag/fall-gardening) - [buying a greenhouse (12)](https://blog.bcgreenhouses.com/tag/buying-a-greenhouse) - [greenhouse plans (12)](https://blog.bcgreenhouses.com/tag/greenhouse-plans) - [summer greenhouse garden (12)](https://blog.bcgreenhouses.com/tag/summer-greenhouse-garden) - [greenhouse maintenance (11)](https://blog.bcgreenhouses.com/tag/greenhouse-maintenance) - [planning for a greenhouse (11)](https://blog.bcgreenhouses.com/tag/planning-for-a-greenhouse) - [Spring garden (10)](https://blog.bcgreenhouses.com/tag/spring-garden) - [fall greenhouse (9)](https://blog.bcgreenhouses.com/tag/fall-greenhouse) - [grow your own food (9)](https://blog.bcgreenhouses.com/tag/grow-your-own-food) - [First-time Greenhouse Owner (8)](https://blog.bcgreenhouses.com/tag/first-time-greenhouse-owner) - [garden (8)](https://blog.bcgreenhouses.com/tag/garden) - [greenhouse buying (8)](https://blog.bcgreenhouses.com/tag/greenhouse-buying) - [greenhouse tomatoes (8)](https://blog.bcgreenhouses.com/tag/greenhouse-tomatoes) - [Summer Greenhouse (7)](https://blog.bcgreenhouses.com/tag/summer-greenhouse) - [feature (7)](https://blog.bcgreenhouses.com/tag/feature) - [greenhouse kit (7)](https://blog.bcgreenhouses.com/tag/greenhouse-kit) - [shade cloth (7)](https://blog.bcgreenhouses.com/tag/shade-cloth) - [spring greenhouse (7)](https://blog.bcgreenhouses.com/tag/spring-greenhouse) - [custom greenhouses (6)](https://blog.bcgreenhouses.com/tag/custom-greenhouses) - [greenhouse cooling (6)](https://blog.bcgreenhouses.com/tag/greenhouse-cooling) - [Greenhouse Glazing (5)](https://blog.bcgreenhouses.com/tag/greenhouse-glazing) - [Greenhouse Temperature (5)](https://blog.bcgreenhouses.com/tag/greenhouse-temperature) - [News (5)](https://blog.bcgreenhouses.com/tag/news) - [aluminum greenhouse (5)](https://blog.bcgreenhouses.com/tag/aluminum-greenhouse) - [family business (5)](https://blog.bcgreenhouses.com/tag/family-business) - [gardening (5)](https://blog.bcgreenhouses.com/tag/gardening) - [greenhouse foundation (5)](https://blog.bcgreenhouses.com/tag/greenhouse-foundation) - [greenhouse installation (5)](https://blog.bcgreenhouses.com/tag/greenhouse-installation) - [soil (5)](https://blog.bcgreenhouses.com/tag/soil) - [strong greenhouse (5)](https://blog.bcgreenhouses.com/tag/strong-greenhouse) - [tomatoes (5)](https://blog.bcgreenhouses.com/tag/tomatoes) - [traditional greenhouse (5)](https://blog.bcgreenhouses.com/tag/traditional-greenhouse) - [Summer Heat (4)](https://blog.bcgreenhouses.com/tag/summer-heat) - [glass house (4)](https://blog.bcgreenhouses.com/tag/glass-house) - [75th Anniversary (3)](https://blog.bcgreenhouses.com/tag/75th-anniversary) - [Company History (3)](https://blog.bcgreenhouses.com/tag/company-history) - [Greenhouse Ventilation (3)](https://blog.bcgreenhouses.com/tag/greenhouse-ventilation) - [Tomatoe Growing (3)](https://blog.bcgreenhouses.com/tag/tomatoe-growing) - [cooling a greenhouse (3)](https://blog.bcgreenhouses.com/tag/cooling-a-greenhouse) - [fertilizer (3)](https://blog.bcgreenhouses.com/tag/fertilizer) - [greenhouse business (3)](https://blog.bcgreenhouses.com/tag/greenhouse-business) - [greenhouse vents (3)](https://blog.bcgreenhouses.com/tag/greenhouse-vents) - [starting seeds (3)](https://blog.bcgreenhouses.com/tag/starting-seeds) - [used greenhouse (3)](https://blog.bcgreenhouses.com/tag/used-greenhouse) - [High Winds (2)](https://blog.bcgreenhouses.com/tag/high-winds) - [Lettuce (2)](https://blog.bcgreenhouses.com/tag/lettuce) - [aphids (2)](https://blog.bcgreenhouses.com/tag/aphids) - [best greenhouse (2)](https://blog.bcgreenhouses.com/tag/best-greenhouse) - [budget gardening (2)](https://blog.bcgreenhouses.com/tag/budget-gardening) - [cape cod (2)](https://blog.bcgreenhouses.com/tag/cape-cod) - [commercial greenhouse (2)](https://blog.bcgreenhouses.com/tag/commercial-greenhouse) - [customer testimonial (2)](https://blog.bcgreenhouses.com/tag/customer-testimonial) - [early growing (2)](https://blog.bcgreenhouses.com/tag/early-growing) - [ferticare (2)](https://blog.bcgreenhouses.com/tag/ferticare) - [greenhouse catalog (2)](https://blog.bcgreenhouses.com/tag/greenhouse-catalog) - [greenhouse cleaning (2)](https://blog.bcgreenhouses.com/tag/greenhouse-cleaning) - [greenhouse climate control (2)](https://blog.bcgreenhouses.com/tag/greenhouse-climate-control) - [greenhouse pest control (2)](https://blog.bcgreenhouses.com/tag/greenhouse-pest-control) - [greenhouse pest management (2)](https://blog.bcgreenhouses.com/tag/greenhouse-pest-management) - [greenhouse pests (2)](https://blog.bcgreenhouses.com/tag/greenhouse-pests) - [greenhouse roof vent (2)](https://blog.bcgreenhouses.com/tag/greenhouse-roof-vent) - [heat wave (2)](https://blog.bcgreenhouses.com/tag/heat-wave) - [heating your greenhouse (2)](https://blog.bcgreenhouses.com/tag/heating-your-greenhouse) - [hot climate (2)](https://blog.bcgreenhouses.com/tag/hot-climate) - [hot house (2)](https://blog.bcgreenhouses.com/tag/hot-house) - [investment (2)](https://blog.bcgreenhouses.com/tag/investment) - [lean-to greenhouse (2)](https://blog.bcgreenhouses.com/tag/lean-to-greenhouse) - [placement (2)](https://blog.bcgreenhouses.com/tag/placement) - [replacing bayliss cylinder (2)](https://blog.bcgreenhouses.com/tag/replacing-bayliss-cylinder) - [start planting (2)](https://blog.bcgreenhouses.com/tag/start-planting) - [strength (2)](https://blog.bcgreenhouses.com/tag/strength) - [vent openers (2)](https://blog.bcgreenhouses.com/tag/vent-openers) - [Arugula (1)](https://blog.bcgreenhouses.com/tag/arugula) - [Cauliflower (1)](https://blog.bcgreenhouses.com/tag/cauliflower) - [DIY (1)](https://blog.bcgreenhouses.com/tag/diy) - [Epic Gardening (1)](https://blog.bcgreenhouses.com/tag/epic-gardening) - [Greenhouse Decor (1)](https://blog.bcgreenhouses.com/tag/greenhouse-decor) - [Greenhouse Floors (1)](https://blog.bcgreenhouses.com/tag/greenhouse-floors) - [Greenhouse Site (1)](https://blog.bcgreenhouses.com/tag/greenhouse-site) - [Greenhouse location (1)](https://blog.bcgreenhouses.com/tag/greenhouse-location) - [House and Home (1)](https://blog.bcgreenhouses.com/tag/house-and-home) - [Humidity (1)](https://blog.bcgreenhouses.com/tag/humidity) - [Indiana Wesleyan Greenhouse (1)](https://blog.bcgreenhouses.com/tag/indiana-wesleyan-greenhouse) - [Moisture (1)](https://blog.bcgreenhouses.com/tag/moisture) - [Pacific Greenhouse (1)](https://blog.bcgreenhouses.com/tag/pacific-greenhouse) - [Podcast (1)](https://blog.bcgreenhouses.com/tag/podcast) - [Polycarbonate (1)](https://blog.bcgreenhouses.com/tag/polycarbonate) - [Seeds (1)](https://blog.bcgreenhouses.com/tag/seeds) - [Warranty (1)](https://blog.bcgreenhouses.com/tag/warranty) - [Yew Greenhouse (1)](https://blog.bcgreenhouses.com/tag/yew-greenhouse) - [anniversary (1)](https://blog.bcgreenhouses.com/tag/anniversary) - [bayliss cylinder (1)](https://blog.bcgreenhouses.com/tag/bayliss-cylinder) - [bc greenhouse builders (1)](https://blog.bcgreenhouses.com/tag/bc-greenhouse-builders) - [bulbs (1)](https://blog.bcgreenhouses.com/tag/bulbs) - [charley's greenhouse & garden supply (1)](https://blog.bcgreenhouses.com/tag/charleys-greenhouse-garden-supply) - [chicken coop greenhouse (1)](https://blog.bcgreenhouses.com/tag/chicken-coop-greenhouse) - [cold house (1)](https://blog.bcgreenhouses.com/tag/cold-house) - [composting (1)](https://blog.bcgreenhouses.com/tag/composting) - [cucumbers (1)](https://blog.bcgreenhouses.com/tag/cucumbers) - [deciding on a greenhouse (1)](https://blog.bcgreenhouses.com/tag/deciding-on-a-greenhouse) - [digging foundation (1)](https://blog.bcgreenhouses.com/tag/digging-foundation) - [drop door (1)](https://blog.bcgreenhouses.com/tag/drop-door) - [everlast greenhouses (1)](https://blog.bcgreenhouses.com/tag/everlast-greenhouses) - [feeding plants (1)](https://blog.bcgreenhouses.com/tag/feeding-plants) - [germination (1)](https://blog.bcgreenhouses.com/tag/germination) - [gift (1)](https://blog.bcgreenhouses.com/tag/gift) - [greenhouse berries (1)](https://blog.bcgreenhouses.com/tag/greenhouse-berries) - [greenhouse bugs (1)](https://blog.bcgreenhouses.com/tag/greenhouse-bugs) - [greenhouse organization (1)](https://blog.bcgreenhouses.com/tag/greenhouse-organization) - [greenhouse vent openers (1)](https://blog.bcgreenhouses.com/tag/greenhouse-vent-openers) - [greenhouse watering (1)](https://blog.bcgreenhouses.com/tag/greenhouse-watering) - [gynoecious (1)](https://blog.bcgreenhouses.com/tag/gynoecious) - [holidays (1)](https://blog.bcgreenhouses.com/tag/holidays) - [hurricane (1)](https://blog.bcgreenhouses.com/tag/hurricane) - [new crops (1)](https://blog.bcgreenhouses.com/tag/new-crops) - [plant starts (1)](https://blog.bcgreenhouses.com/tag/plant-starts) - [press release (1)](https://blog.bcgreenhouses.com/tag/press-release) - [rooftop greenhouse (1)](https://blog.bcgreenhouses.com/tag/rooftop-greenhouse) - [sealing a greenhouse (1)](https://blog.bcgreenhouses.com/tag/sealing-a-greenhouse) - [secondhand greenhouse (1)](https://blog.bcgreenhouses.com/tag/secondhand-greenhouse) - [she shed (1)](https://blog.bcgreenhouses.com/tag/she-shed) - [shed (1)](https://blog.bcgreenhouses.com/tag/shed) - [strawberries (1)](https://blog.bcgreenhouses.com/tag/strawberries) - [unique greenhouses (1)](https://blog.bcgreenhouses.com/tag/unique-greenhouses) - [wall street journal (1)](https://blog.bcgreenhouses.com/tag/wall-street-journal) - [watering garden (1)](https://blog.bcgreenhouses.com/tag/watering-garden) - [weather (1)](https://blog.bcgreenhouses.com/tag/weather) - [wind rating (1)](https://blog.bcgreenhouses.com/tag/wind-rating) - [wood greenhouse (1)](https://blog.bcgreenhouses.com/tag/wood-greenhouse) See all [Hannah Nicklas|](https://blog.bcgreenhouses.com/author/hannah-nicklas) 08.21.2026| 17 MIN READ TIME ## Quick Answer:  **Start before the frost hits.** Once nighttime temperatures are consistently dropping into the single digits Celsius (upper 40s Fahrenheit), it is time to clean, check equipment, and add insulation, not wait for a frost warning to show up on the forecast. **Clear out and clean first.** Remove finished summer crops, wash down any plants staying in for winter, and pencil in a deep clean for mid-November before things get too cold to tackle it comfortably. **Check your equipment, then seal in the heat.** Inspect fasteners, vents, and fans while the weather still allows for it, then add insulation, thermal mass, row covers, or soil warming to hold onto heat as temperatures fall. **Ease off watering and switch crops.** Cut back as growth slows down, and swap warm-season plants for cold-hardy crops like kale, spinach, and Swiss chard to keep the greenhouse productive right through winter. **Jump to a Section:** - [Why Fall Greenhouse Prep Matters](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#why-fall-greenhouse-prep-matters) - [When Should You Start Preparing for the First Frost in a Greenhouse?](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#prepping-before-the-first-frost) - [How Do You Clear Out and Clean a Greenhouse Before Winter?](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#clean-greenhouse-before-winter) - [What Equipment and Structural Checks Should You Do Before Cold Weather Hits?](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#greenhouse-equipment-checks-fall) - [How Do You Keep Heat In a Greenhouse as Temperatures Drop?](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#keep-heat-in-greenhouse-fall) - [How Should You Adjust Watering and Plant Care in a Fall Greenhouse?](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#fall-greenhouse-watering-plant-care) - [What Can You Plant in a Greenhouse to Keep Growing Through Fall and Winter?](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#what-to-plant-in-greenhouse-fall-winter) - [Your Fall Greenhouse Prep Checklist at a Glance](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost#fall-greenhouse-prep-checklist) There is a moment every fall when you walk out to the greenhouse and notice it. The air feels different. The glass has a light fog on it in the morning, and the tomatoes that were thriving in August are starting to slow down. That is your sign. Fall is here, and your greenhouse needs a little attention before the cold sets in. ![Cottage greenhouse on foggy morning](https://blog.bcgreenhouses.com/hs-fs/hubfs/Greenhouse%20Exterior/IMG_0247.jpg?width=1024&name=IMG_0247.jpg "Cottage greenhouse on foggy morning")   The good news is that fall prep does not have to mean shutting things down. With the right cleaning, a few structural checks, and some smart insulation, your greenhouse can keep producing food and providing a warm, green escape well past the first frost. This guide walks you through everything to do before the temperature drops, from clearing out summer crops to choosing what to plant next. ## Why Fall Greenhouse Prep Matters It is tempting to let the greenhouse coast once the peak of summer growing is behind you. But the tasks you skip in September tend to show up as problems in December. Leftover summer growth invites pests and disease to overwinter alongside your plants. A vent that sticks in October will only get harder to fix once it is covered in frost. And a greenhouse that loses heat overnight can undo a whole season of care in a single cold snap. A little bit of fall prep protects the investment you have already made, and it sets you up to keep growing right through the colder months instead of putting everything on pause. ## When Should You Start Preparing for the First Frost in a Greenhouse? [Frost dates](https://www.almanac.com/gardening/frostdates) vary depending on where you are, but the safest approach is to start preparing well before the forecast calls for it. Watch for the early signs: - Cooler nights - Morning dew that lingers longer - A noticeable dip in evening temperatures inside the greenhouse Once nighttime temperatures are consistently dropping into the single digits Celsius or the 40s Fahrenheit, it is time to move from "keeping an eye on it" to actively prepping.  Waiting until a frost warning shows up on the forecast puts you in reactive mode. Starting a few weeks earlier gives you time to clean, check your equipment, and get insulation in place without scrambling.  - ![My April Greenhouse - Cleaning (Twitter Post)](https://blog.bcgreenhouses.com/hs-fs/hubfs/Greenhouse%20Exterior/My%20April%20Greenhouse%20-%20Cleaning%20(Twitter%20Post).png?width=1600&height=900&name=My%20April%20Greenhouse%20-%20Cleaning%20(Twitter%20Post).png) - ![Capture1](https://blog.bcgreenhouses.com/hs-fs/hubfs/Greenhouse%20Exterior/Capture1.png?width=1006&height=778&name=Capture1.png) - ![248229089_964758694254182_4861917912898234075_n](https://blog.bcgreenhouses.com/hs-fs/hubfs/Greenhouse%20Exterior/248229089_964758694254182_4861917912898234075_n.jpeg?width=607&height=873&name=248229089_964758694254182_4861917912898234075_n.jpeg) ## How Do You Clear Out and Clean a Greenhouse Before Winter Sets In? A clean greenhouse going into fall is a healthier greenhouse coming out of winter. This is the point in the season to take stock of what stays and what goes. ### Remove Summer Crops and Debris If you are extending your season, pull out any summer crops that have finished producing. Leaving spent plants in place invites disease and gives pests a place to settle in for the winter. Clear out fallen leaves, dead foliage, and anything that could start to rot once the greenhouse cools down. ### Treat and Clean Overwintering Plants For plants that are sticking around, give them a proper check before the weather turns. Wash the leaves with a soft, soapy cloth and look closely for pests or signs of disease. Cool nights paired with warm days can encourage sooty mold to grow. If you spot it, a Q-tip dipped in alcohol will take care of small patches. Once your plants are clean, cover them with a protective fleece for extra frost protection over winter.  ![sooty mold](https://blog.bcgreenhouses.com/hs-fs/hubfs/Blog%20Content/sooty%20mold.jpg?width=1280&name=sooty%20mold.jpg "sooty mold")   ### Plan Your Deep Clean for Mid-November Many greenhouse owners do a full deep clean in mid-November, right before settling in for winter. Empty the greenhouse completely so you can get into every corner. A shop vacuum is your best friend here, and not just for the floor. Run it along the walls, interior bolt tracks, door thresholds, vent screens, and weather stripping, anywhere pests like to hide. A pressure washer on a low setting works well for a deeper clean. If you have polycarbonate panels, take care around the silicone seals so water does not get into the flutes, and skip the acetone or paint thinners since they will damage most glazing materials. Naptha is the safe choice for spot cleaning polycarbonate. ## What Equipment and Structural Checks Should You Do Now? Fall is the right time to make sure everything mechanical and structural is ready to handle colder weather. ![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Installations/DSC_0064.jpg?width=350&name=DSC_0064.jpg) #### Check Fasteners and Glazing Walk the greenhouse with a level and check the foundation and glazing bars on either side of the doors. If you are in a windy area, a bit of Loctite on the side bolts helps keep things secure through fall and winter. ![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Accessories/Exhaust%20Fan%20Interior-JPG.jpeg?width=350&name=Exhaust%20Fan%20Interior-JPG.jpeg) #### Secure Fans and Vents Close off any vents and fans you will not need over winter to prevent drafts and heat loss. If you have a horizontal air flow fan, that is a good time to clean and service if for the year ahead. ![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Foundation%20Carousel%20Instagram%20(1).png?width=350&name=Foundation%20Carousel%20Instagram%20(1).png) #### Inspect Foundation and Drainage Check your foundation for gaps or cracks that could let in critters, and make sure any drainage grates are clear of dirt, leaves, or stones before the fall rains arrive. ![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Charleys/N2616-c__31739.jpeg?width=350&name=N2616-c__31739.jpeg) #### Calibrate Your Thermometer A quick check against a digital thermometer ensures you are getting an accurate read on your greenhouse temperature all winter long, which matters more than ever once you start relying on it to pretect your plants overnight.   ### Troubleshoot Roof Vent Cylinders If a roof vent is not opening the way it used to, the wax cylinder inside may just need a kickstart. Remove the cylinder, place it in the refrigerator (not the freezer) for 30 minutes, then run it under hot water for 5 to 10 minutes. If that doesn't do the trick, it is likely time for a replacement. [Wax cylinders](https://shop.charleysgreenhouses.com/collections/repair-shop/products/bayliss-solar-vent-power-tube-replacement) typically last 5 to 7 years, and if you would rather remove the guesswork from a windy winter, you can take the hinge off entirely and secure the vent closed with wire or zip straps.    ## How Do You Keep Heat In as Temperatures Drop? Once your Greenhouse is clean and checked over, it is time to think about heat retention. ### Line Your Greenhouse for Extra Insulation A layer of clear 4mm plastic or bubble wrap along the inside of the greenhouse can make a real difference in how much heat you retain. Insulating clips or short pieces of rope tucked into the bolt track will hold it in place. ### Use Thermal Mass to Your Advantage If your greenhouse gets some solar gain even in the colder months, try placing black barrels filled with water inside. They soak up heat during the day and slowly release it overnight, acting as a simple thermal battery. ![image-png-1](https://blog.bcgreenhouses.com/hs-fs/hubfs/image-png-1.png?width=323&name=image-png-1.png "image-png-1")   ### Add Frost Protection With Row Covers A layer of Agribon fleece adds meaningful frost protection, anywhere from 2 to 7°  C or 35 to 44° F depending on the weight you choose. The higher the number, the more protection it offers, and it is a low-tech solution that goes a long way. ### Warm the Soil, Not Just the Air Sometimes the most efficient fix is warming the root zone directly. Waterproof soil warming cables laid under your pots give plants a cozy boost without heating the whole greenhouse. [![Free E-Book Extreme Weather & Maintenance Guide  A comprehensive guide that includes tips straight from the experts. This guide is intended for those customers who have purchased and received their greenhouse.   ](https://no-cache.hubspot.com/cta/default/19607244/interactive-220041463220.png)](https://blog.bcgreenhouses.com/hs/cta/wi/redirect?encryptedPayload=AVxigLJmpWOWOssNUL9KWKxlwASKc3IcjWVeKqid2oFzU02YNnh%2FXqaTtEnIyp9pIKstDWp4C3hBMnYLkKop3Nqi0Onwsg6DG2IK1MWTypIou%2FTDke7jqHkY6vXpFWEorkR600uHz6IXRa%2FOJ%2Fp8WqP9B7IkfqZIm%2FZM3UJpTQF1xyAHk6PjSwKrwoA6IuBmKgLYKI%2BjtBBGmuaUiUIadC7BpJ0%2B6RbYH%2B%2BhWhv0fIfo3ZyO&webInteractiveContentId=220041463220&portalId=19607244) ### Automate With a Thermostat Pairing a space heater with a thermostat means your greenhouse stays protected whether you are at your desk or asleep. The thermostat regulates the heater as needed and lets the sun do the work once solar gain kicks in during the day. ### Keep Air Moving A circulating fan running around the clock, in both winter and summer, helps prevent the cold pockets where frost damage tends to start. Moving air is far less likely to freeze than air trapped in a still corner of the greenhouse. ![C3068__11703](https://blog.bcgreenhouses.com/hs-fs/hubfs/C3068__11703.jpg?width=876&name=C3068__11703.jpg "C3068__11703") ## How Should You Adjust Watering and Plant Care Going Into Fall? ### Cut Back on Watering As growth slows down, so should your watering. Sitting water in cooler soil created the perfect conditions for fungus gnats to move in. Most winter crops shift into a kind of holding mode, growing slowly and needing far less water than they did in summer. In some cases, it makes sense to stop watering certain plants altogether until spring. ### Wash Row Covers Before You Use Them If you are pulling out fabric row covers for the season, run them through a hot wash first. Starting clean helps keep pests and disease from getting a head start under the fabric. ## What Can You Plant Now to Keep Growing Through Fall and Winter Fall does not have to mean the end of your growing season. It just means switching to plants that can handle the cold. ![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Blog%20Content/Green%20Tips.jpg?width=350&name=Green%20Tips.jpg) #### Cold-Hardy Vegetables to Try - Spinach - Mustard Greens - Arugula - Kale - Beets - Carrots - Swiss Chard All these do well in a cool greenhouse. Many of these can freeze solid and bounce right back once temperatures rise again, making them some of the most forgiving crops for a fall and winter garden. ![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Blog%20Content/lemons.jpg?width=350&name=lemons.jpg) #### Cold- Tolerant Plants for Milder Greenhouses If your greenhouse stays just above freezing, plants like the following can tolerate a light frost: - Meyer lemons - Hardy cactus - Olives These will keep your greenhouse feeling green through the darker months.   ## Your Fall Greenhouse Prep Checklist at a Glance 1. Watch for cooling nights and start prepping before frost is forecast 2. Remove spent summer crops and clean up debris 3. Wash and inspect any plants staying in for winter 4. Schedule a deep clean for mid-November 5. Check fasteners, glazing, and foundation for gaps or shifting 6. Service fans and troubleshoot any sticky roof vents 7. Add insulation, thermal mass, row covers, or soil warming as needed 8. Set up a thermostat-controlled heater and keep a fan running continuously 9. Cut back on watering and wash row covers before use 10. Choose cold-hardy crops to keep the greenhouse productive all season ![IMG_6920](https://blog.bcgreenhouses.com/hs-fs/hubfs/IMG_6920.jpeg?width=1500&height=2000&name=IMG_6920.jpeg "IMG_6920")   A little preparation now means a greenhouse that keeps giving you fresh produce, warm air, and a reason to head outside, long after the rest of the garden has gone quiet for the year. [![Mailed or Digital BC Greenhouse Catalogs Discover all our models, read real customer stories, and plan your dream garden today!  ](https://no-cache.hubspot.com/cta/default/19607244/interactive-202015591596.png)](https://blog.bcgreenhouses.com/hs/cta/wi/redirect?encryptedPayload=AVxigLLQb%2Ffx2BhaNQ8vD%2BiWQgBfvXly7%2BdON7RL%2Fn2WpHPXC2Os7uMaHFiuCnXv91uLZQMCpuNKtYu08WwK3UcSyBN08zq8WzohPU5QsroMFGPzhLlkfEK%2BFaUpcVIWFnHTh8zoLzmR6zPJBFCaTG6ql0z11d%2F8kxEa3wF3N8g4oDabQhIvXuIxczTBrYszws%2FaX6wRvlunQZFDaZEE&webInteractiveContentId=202015591596&portalId=19607244) ## Related/Recent Blogs #### [![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Greenhouse%20Interior/BC%20Greenhouses%20Fall%20Sale.jpg?width=350&name=BC%20Greenhouses%20Fall%20Sale.jpg) by Hannah Nicklas | 08.21.2026 | 24 min Fall Greenhouse Prep: What to Do Before the First Frost Quick Answer: Start before the frost hits. Once nighttime temperatures are consistently dropping into the single digits Celsius (upper 40s Fahrenheit), it is time to clean, check equipment, and add in... Read More garden preparation, Fall gardening, fall greenhouse](https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost) #### [![](https://blog.bcgreenhouses.com/hs-fs/hubfs/Greenhouse%20interior.jpg?width=350&name=Greenhouse%20interior.jpg) by Trevor Dueck | 08.10.2026 | 17 min How Can You Decorate Your Greenhouse to Create a Personal Oasis? Quick Answer: Read More greenhouse tomatoes, greenhouse, growing in a greenhouse, greenhouse cooling, Summer Heat](https://blog.bcgreenhouses.com/how-can-you-decorate-your-greenhouse-to-create-a-personal-oasis) #### [![](https://blog.bcgreenhouses.com/hs-fs/hubfs/IMG_5365.jpg?width=350&name=IMG_5365.jpg) by Trevor Dueck | 06.29.2026 | 13 min What Are the 5 Strategies for Reducing Mold and Fungus Problems in Greenhouses? Quick Answer: Read More greenhouses, seeding, garden preparation, BC Greenhouse, BC Greenhouses, greenhouse tomatoes, small greenhouse kit, greenhouse tips, growing food, garden transition, greenhouse gardening, greenhouse maintenance, greenhouse, growing in a greenhouse, shade cloth, greenhouse cooling, Greenhouse Temperature, Summer Heat, Greenhouse Ventilation, Tomatoe Growing](https://blog.bcgreenhouses.com/what-are-the-5-strategies-for-reducing-mold-and-fungus-problems-in-greenhouses) [Contact Us](https://www.bcgreenhouses.com/contact-us/)   |   [View Catalog](https://www.bcgreenhouses.com/resources/catalog-request/)   |   [Instant Pricing  ](https://www.bcgreenhouses.com/design-your-own/) |   [Buying Tips  ](https://www.bcgreenhouses.com/greenhouse-buying-tips/) |   [Greenhouse Warranty](https://www.bcgreenhouses.com/resources/warranty/)   |   [Technical Support](https://help.bcgreenhouses.com/knowledge/technical-support)   |   [Financing](https://www.bcgreenhouses.com/financing/) BC Greenhouses is a leading provider of high-quality, customizable greenhouse solutions that ship all over North America. With a wide range of greenhouse models and accessories, we help gardeners, farmers, and horticulture enthusiasts create the perfect environment for their plants. Our expert team is dedicated to delivering exceptional customer service and ensuring that our customers’ greenhouse needs are met. Whether you’re a beginner or an experienced gardener, BC Greenhouses offers the tools and expertise to help you grow your plants with success. Explore our website to discover our extensive greenhouse selection and start building your dream greenhouse today! **© BC Greenhouse Builders Ltd.** All Rights Reserved.   |   [Privacy Policy](https://www.bcgreenhouses.com/privacy-policy/) [![bc_greenhouses_logos_hires-2-white-1024x426](https://blog.bcgreenhouses.com/hs-fs/hubfs/Imported%20sitepage%20images/bc_greenhouses_logos_hires-2-white-1024x426.png?width=340&height=141&name=bc_greenhouses_logos_hires-2-white-1024x426.png "bc_greenhouses_logos_hires-2-white-1024x426")](https://www.bcgreenhouses.com/) [Follow us on Facebook](http://www.houzz.com/pro/bcgreenhouse/bc-greenhouse-builders-ltd) [Follow us on Facebook](https://www.facebook.com/pages/BC-Greenhouse-Builders/119793134732401) [Follow us on Instagram](https://instagram.com/bc_greenhouses/) [Follow us on LinkedIn](https://www.youtube.com/channel/UCz1Hjzda4kEupChtDH0-iMw) [Follow us on Twitter](https://www.pinterest.com/angeladrake/bc-greenhouse-builders/) ![bbb-logo](https://blog.bcgreenhouses.com/hs-fs/hubfs/bbb-logo.webp?width=125&height=50&name=bbb-logo.webp "bbb-logo") 1-888-391-4433 ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Hannah Nicklas", "url" : "https://blog.bcgreenhouses.com/author/hannah-nicklas" }, "dateModified" : "2026-09-11T01:33:20.934Z", "datePublished" : "2026-08-21T22:53:19.000Z", "headline" : "Fall Greenhouse Prep: What to Do Before the First Frost", "image" : [ "https://blog.bcgreenhouses.com/hubfs/Greenhouse%20Interior/BC%20Greenhouses%20Fall%20Sale.jpg" ], "mainEntityOfPage" : { "@id" : "https://blog.bcgreenhouses.com/fall-greenhouse-prep-what-to-do-before-the-first-frost", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://blog.bcgreenhouses.com/hubfs/bcg-ftr-logo.png" }, "name" : "BC Greenhouse Builders Ltd." } } ``` ```json { "@context" : "https://schema.org", "@type" : "VideoObject", "contentUrl" : "https://19607244.fs1.hubspotusercontent-na1.net/hubfs/19607244/social-suggested-images/Replacing%20Roof%20Vent%20Cylinder%20Video.mp4", "dateModified" : "2025-01-26T16:56:20.666Z", "duration" : "PT2M59.947S", "height" : 1080, "name" : "Replacing Roof Vent Cylinder Video", "thumbnailUrl" : "https://19607244.fs1.hubspotusercontent-na1.net/hubfs/19607244/social-suggested-images/Replacing%20Roof%20Vent%20Cylinder%20Video.mp4/medium.jpg?t=1737910580666", "uploadDate" : "2022-07-25T21:50:23.359Z", "width" : 1920 } ``` ```json { "@context" : "https://schema.org", "@type" : "FAQPage", "mainEntity" : [ { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Skipping fall greenhouse prep often turns into bigger problems later. Leftover summer growth can invite pests and disease to overwinter with your plants, a sticking vent gets harder to fix once it is covered in frost, and a greenhouse that loses heat overnight can undo a whole season of care in one cold snap. A little preparation now protects your investment and keeps your greenhouse productive through the colder months instead of shutting it down." }, "name" : "Why does fall greenhouse prep matter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Skipping fall maintenance can let leftover summer growth invite pests and disease to overwinter with your plants. Vents that start sticking in October only get harder to fix once they are covered in frost, and a greenhouse that loses heat overnight in a single cold snap can undo an entire season of care." }, "name" : "What problems can happen if you skip fall greenhouse maintenance?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Start preparing before nighttime temperatures consistently drop into the single digits Celsius, or the upper 40s Fahrenheit, rather than waiting for a frost warning. Beginning a few weeks ahead of the first frost gives you time to clean, check equipment, and add insulation without scrambling." }, "name" : "When should you start preparing your greenhouse for the first frost?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Watch for cooler nights, morning dew that lingers longer than usual, and a noticeable dip in evening temperatures inside the greenhouse. These early signs mean it is time to start prepping rather than wait for a frost warning." }, "name" : "What are the early signs that frost season is approaching in a greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Once nighttime temperatures are consistently dropping into the single digits Celsius, or the upper 40s Fahrenheit, it is time to move from keeping an eye on the forecast to actively winterizing your greenhouse." }, "name" : "What temperature should trigger you to start winterizing your greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Waiting for a frost warning puts you in reactive mode. Starting a few weeks earlier gives you time to clean, check your equipment, and get insulation in place without scrambling at the last minute." }, "name" : "Why shouldn't you wait for a frost warning to prep your greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Pull out any summer crops that have finished producing, since leaving spent plants in place invites disease and gives pests a place to settle in for winter. Clear out fallen leaves and dead foliage too, since anything left behind can start to rot once the greenhouse cools down." }, "name" : "What should you do with spent summer crops before winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Wash the leaves of plants staying in the greenhouse with a soft, soapy cloth and check closely for pests or disease. If you spot sooty mold, treat small patches with a Q-tip dipped in alcohol. Once the plants are clean, cover them with a protective fleece for extra frost protection over winter." }, "name" : "How do you prepare overwintering plants for the cold season?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Sooty mold can be treated by dipping a Q-tip in alcohol and using it on small patches. It tends to show up when cool nights are paired with warm days, so keep an eye out for it as fall temperatures start to swing." }, "name" : "How do you treat sooty mold on greenhouse plants?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "BC Greenhouse Builders recommends scheduling a full deep clean in mid-November, right before settling in for winter. This timing lets you empty the greenhouse and clean every corner before the cold really sets in." }, "name" : "When should you do a deep clean of your greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Empty the greenhouse completely so you can access every corner, then use a shop vacuum on the floor, walls, interior bolt tracks, door thresholds, vent screens, and weather stripping, anywhere pests like to hide. Finish with a pressure washer on a low setting for a deeper clean." }, "name" : "How do you deep clean a greenhouse before winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Take care around the silicone seals so water does not get into the flutes when pressure washing polycarbonate panels. Skip acetone or paint thinners, since they will damage the material, and use Naptha instead for spot cleaning." }, "name" : "How do you clean polycarbonate greenhouse panels safely?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Yes, a pressure washer on a low setting works well for a deeper clean of a greenhouse. Just take extra care around silicone seals on polycarbonate panels so water does not get into the flutes." }, "name" : "Can you use a pressure washer on a greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Walk the greenhouse with a level and check the foundation and glazing bars on either side of the doors for any signs of shifting or settling." }, "name" : "How do you check if a greenhouse foundation has shifted?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Yes, if you are in a windy area, a bit of Loctite on the interior bolts helps keep everything secure through fall and winter storms." }, "name" : "Should you use Loctite on greenhouse bolts in windy areas?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Closing off any vents and fans you will not need over winter prevents drafts and unnecessary heat loss once the weather turns cold." }, "name" : "Why should you close greenhouse vents and fans in winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Fall is a good time to clean and service a horizontal air flow, or HAF, fan each year so it is ready to keep air moving through the colder months." }, "name" : "How often should you service a greenhouse HAF fan?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "If a roof vent has stopped opening properly, the wax cylinder inside may just need a kickstart. Remove the cylinder, place it in the refrigerator, not the freezer, for 30 minutes, then run it under hot water for 5 to 10 minutes. If that does not solve it, the cylinder likely needs replacing. You can also remove the hinge entirely and secure the vent closed with wire or zip straps for the winter." }, "name" : "How do you fix a greenhouse roof vent that won't open in winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Wax vent cylinders typically last 5 to 7 years before they need replacing. If a warm water and refrigerator trick does not get a sluggish vent moving again, it is likely time for a new cylinder." }, "name" : "How long do greenhouse wax vent cylinders last?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Check your foundation for gaps or cracks that could let in critters, and make sure any drainage grates are clear of dirt, leaves, or stones before fall rains arrive." }, "name" : "How do you check greenhouse drainage before winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Calibrating your thermometer against a digital one ensures you are getting an accurate temperature reading all winter long, which matters most once you are relying on it to protect your plants overnight." }, "name" : "Why should you calibrate a greenhouse thermometer?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "A layer of clear 4mm plastic or bubble wrap along the inside of the greenhouse can make a real difference in heat retention. Insulating clips or short pieces of rope tucked into the bolt track will hold it in place." }, "name" : "How do you insulate a greenhouse with plastic or bubble wrap?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Thermal mass refers to materials that soak up heat during the day and slowly release it overnight. Placing black barrels filled with water inside a greenhouse that gets some solar gain is a simple way to create that thermal battery effect." }, "name" : "What is thermal mass and how does it help a greenhouse in winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "A layer of Agribon fleece adds anywhere from 2 to 7 degrees Celsius, or 35 to 44 degrees Fahrenheit, of frost protection depending on the weight you choose. The higher the number, the more protection it offers." }, "name" : "How much frost protection does Agribon fleece provide?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Soil warming cables are waterproof cables laid under pots to warm the root zone directly. This gives plants a cozy boost without needing to heat the entire greenhouse." }, "name" : "What are soil warming cables and how do they help greenhouse plants?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Pairing a space heater with a thermostat keeps a greenhouse protected automatically, whether you are at your desk or asleep. The thermostat regulates the heater as needed and lets the sun do the work once solar gain kicks in during the day." }, "name" : "How does a thermostat help regulate greenhouse heat?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "A circulating fan running around the clock helps prevent the cold pockets where frost damage tends to start, since moving air is far less likely to freeze than air trapped in a still corner of the greenhouse." }, "name" : "Why should a greenhouse fan run continuously in winter?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "As plant growth slows down in fall, so should your watering. Sitting water in cooler soil creates ideal conditions for fungus gnats, and most winter crops shift into a holding mode where they need far less water than they did in summer." }, "name" : "Why should you cut back on watering a greenhouse in fall?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Yes, running fabric row covers through a hot wash before using them helps keep pests and disease from getting a head start under the fabric." }, "name" : "Should you wash row covers before using them?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Spinach, mustard greens, arugula, kale, beets, carrots, and swiss chard are all cold-hardy vegetables that do well in a cool greenhouse. Many of them can freeze solid and bounce back once temperatures rise again." }, "name" : "What cold-hardy vegetables can survive freezing in a greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Meyer lemons, hardy cactus, and olives can all tolerate a light frost, making them good choices for a greenhouse that stays just above freezing through winter." }, "name" : "What plants tolerate light frost in a greenhouse?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "A complete fall greenhouse prep checklist includes watching for cooling nights and starting prep before frost is forecast, removing spent summer crops, washing and inspecting overwintering plants, scheduling a mid-November deep clean, checking fasteners and glazing, servicing fans and vents, adding insulation and heat sources, cutting back on watering, and switching to cold-hardy crops. BC Greenhouse Builders walks through each of these steps in detail to help you get ready before the first frost." }, "name" : "What should be on a fall greenhouse prep checklist?" } ] } ```