Quick Answer:

How do I keep my greenhouse thriving in June? June greenhouse success starts with proactive heat management, consistent watering, and increased pest awareness as temperatures rise and growth accelerates. What should be on my June greenhouse checklist? Prioritize ventilation tune-ups, shade cloth installation, pest scouting, structural checks, and regular feeding to support rapid plant development and prevent stress. Why is June maintenance important? Small seasonal adjustments now—like updating irrigation systems or refreshing crops—ensure healthier plants, better yields, and a more enjoyable greenhouse experience all summer long.

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June is when things really start to take off in the greenhouse. The sunlight is strong, the days are long, and plant growth shifts into overdrive. But just as the growing season ramps up, so do the demands on your greenhouse setup. From rising temperatures to increased pest activity, a little prep work now can make all the difference.

Explore effective strategies to keep your greenhouse cool and thriving during the summer season.

Quick Answer: 

What are the best tips for a successful late summer greenhouse harvest? As the season transitions, focus on four essential strategies: switch to a low-nitrogen fertilizer (like a 2-8-4 mix with kelp and micronutrients) to build plant strength without promoting excessive growth; maintain strong air circulation with fans to prevent fungal issues as nights cool; start fresh crops like lettuce and arugula to extend your harvest into fall; and apply targeted shading using aluminet or shade cloth to protect plants from intense late-summer sun. These greenhouse gardening tips will help you maximize yields and enjoy a longer, more productive harvest season.

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Late Summer Gardening Tips

It is late August and I am chatting with my daughter who lives in Northern Alberta, Canada. Her outside garden has never looked so good because of the heat and regular rains. But she is wishing she could get another month on either end of the growing season.

Quick Answer:

Why grow your own lettuce this season? Growing full-size head lettuce in your greenhouse garden brings unmatched freshness, variety, and taste compared to store-bought bagged greens. Head lettuces like romaine, butter, crisphead, and leaf types offer richer textures, better crunch, and longer shelf life. They’re ideal for salads, wraps, and sandwiches—and thrive in small spaces between larger greenhouse crops. With easy care, seed-saving potential, and improved nutrition from organic soil, homegrown lettuce is a flavorful, sustainable upgrade to your garden. Rediscover the joy of harvesting crisp, nutrient-packed greens right outside your door.

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If you watch old re-runs on Netflix you have seen how fashions and styles have changed dramatically since Seinfeld was filmed in the 1990s. The same is true for food – especially lettuce.

I first wrote about “novel” mesclun greens (mixed lettuce) in 1995. Since then, they have become so popular, that bagged lettuce is the only lettuce most people know. And this is too bad because lettuce greens or bagged greens are really just immature greens like kale and lettuce leaves. So, for something completely novel, why not go back to the future? Grow full-size head lettuce in your Greenhouse Garden this year.

Most people don’t remember life before the small bags of lettuce leaves so commonly sold now at big box stores and local farm markets. But if you want the crunch of lettuce in a BLT sandwich or if you want to replace Pita bread with a Keto-friendly lettuce leaf wrap for lunch, then start growing your own heads of lettuce this season.

Quick Answer:

What Are the Tips for Growing Greenhouse Tomatoes in the Heat?
To prevent heat stress and flower drop in greenhouse tomatoes, use 40-70% shade cloth to reduce temperature and light intensity, maintain good air circulation with fans and open screen doors, and regularly water soil and paths to cool the environment and increase humidity. Selecting heat-tolerant tomato varieties, like smaller-fruited types or proven heirlooms such as Juliet and Cherokee Purple, helps ensure fruit set during hot spells. Combining these strategies allows growers to maximize tomato yields and extend the harvest season even in extreme summer heat.

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The Trouble with Greenhouse Tomatoes

Do your greenhouse tomatoes have heat stroke?

If your tomato blooms are bending and falling off, flower and all, they are having a heatstroke. When extreme heat hits, greenhouse tomatoes fail to set fruit even as the leaves keep growing and new blooms appear.

 

Pests, Worm Castings and Algae

What are Worm Castings?

Before we get to greenhouse gardening algae, let's talk about a shopper on Amazon that complained about bugs in her worm castings. If you don’t speak garden lingo yet, worm castings are simply worm poop. They are mixed with soil in garden beds or in pots to make tomatoes grow faster, stronger and healthier. And just in case you missed the memo, worm poop comes with bugs of its own. The good ones.

So Many Tomatoes, So Little Space

Greenhouse tomato growers are rightfully confused when they see so many kinds of greenhouse tomatoes for sale. Karen Olivier, an independent tomato breeder from the Secret Seed Cartel, estimates there are 20,000 kinds of tomatoes listed right now and she is adding to that number by breeding new tomatoes every year.

 

Quick Answer:

What Are the Best Tips for Soil Amendments & Nutrients in a Greenhouse Garden?
Optimizing greenhouse soil requires building “super soil” by blending quality soil-less mix with compost, biochar, and worm castings, plus adding essential nutrients like nitrogen, phosphorus, potassium, calcium, and micronutrients through amendments such as seed meals, lime, kelp, and gypsum. Recognizing nutrient deficiency signs—like purple leaves from low phosphorus or brown spots from potassium shortage—helps timely fertilization and soil management, ensuring healthy plant growth and improved crop flavor. Regular soil amendment and fertilization tailored to plant needs foster vibrant, productive greenhouse gardens year-round.

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Importance of Soil Amendments & Nutrients in Greenhouse Gardening

A few years back my greenhouse tomato leaves were purple, yellow and spotted. Not all at once, but over time and on different leaves. It was the second year I was growing in my greenhouse and the commercial potting soil I bought was low on phosphorus, nitrogen and potassium. The leaves on the plants were telling me what was going on. And it didn’t look good.

My tomatoes are sitting beside me in the front seat of my shiny black station wagon. We are on our way to the fair! 

Quick Answer:

Why Should I Start My Fall Crops Now?
Starting fall crops in August maximizes your greenhouse space by replacing summer plants like zucchini or lettuce with fast-growing cool-season crops such as radish, kale, peas, and spinach. This strategic transition extends your harvest into fall and winter while allowing you to propagate strawberries, collect seeds, and prepare transplants. By planning now, you create a continuous cycle of fresh food, making your greenhouse more productive year-round.

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August Plants

August crops are growing so fast that I should have a time-lapse camera to record the speedy growth. It’s a good thing I’m home all month to watch the changes and get the next crops planted and growing.  Check out my tips to grow your own food too!