Quick Answer:

What are the essential seed terms for greenhouse gardening? Understanding common seed terminology is key when planning your greenhouse garden. Heirloom seeds are stable, open-pollinated varieties that grow true from saved seed, while hybrid (F1) seeds are lab-created crosses offering traits like disease resistance or high yield but cannot be reliably saved. F2–F5 seeds are later generations from hybrids, gradually stabilizing into your own heirlooms. Pelleted seeds are clay-coated for ease of planting, especially by machine, while treated seeds are coated with chemicals to resist rot in cold soil—something many organic growers prefer to avoid. Terms like “new” may refer only to catalogue listings, not to truly new varieties. You’ll also see micro-tomatoes, compact plants ideal for greenhouses, and days to maturity, which are useful for comparing growth speeds across varieties but are not precise. Ultimately, buying seeds in bulk from fewer suppliers or saving your own seed helps manage rising shipping costs while still offering variety and value in your greenhouse garden.

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So much to consider

It is December and the seed catalogues are arriving fast and furious. Meanwhile, online suppliers are pounding out dozens of notices to remind us it is time to order seeds soon.