How to Design a Year-Round Growing Plan With Your Greenhouse
Many gardeners and homesteaders think greenhouses are only useful in spring. But with the right strategy, a well-built high tunnel or hoop house can help you grow food in all four seasons — even in northern climates where winters are cold and sunlight is limited.
While year-round growing doesn’t mean tomatoes in January without heat and lights, it does mean you can keep fresh greens on your plate, harvest hardy vegetables into the dead of winter, and get a serious jump on the growing season before the last frost.
Here’s how to build a smart, realistic, and productive year-round greenhouse growing plan, especially if you’re working with an unheated or minimally heated structure like the ones we build here at Sunbow.
Understanding the Seasons in an Unheated Greenhouse
Before you can plan effectively, it helps to break the year into four distinct greenhouse seasons, each with its own rhythm and purpose:
Spring (early to late): Starting seeds, transplanting hardy crops, harvesting overwintered greens.
Summer: Growing heat-loving crops; ventilation and shade are key.
Fall: Transition crops, seed cold-hardy greens and roots.
Winter: Growing slows down, but cold-hardy crops persist and can be harvested without actively growing.
In northern zones, winter light levels and soil temps drop too low to support fast growth — but that doesn’t mean your greenhouse is idle. It becomes a living pantry, holding food in the ground for weeks or months.
Choosing the Right Crops for Each Season
A successful year-round plan depends on choosing crops suited to the season and temperature, especially in a passive (unheated) structure.
Spring
Start indoors: Tomatoes, peppers, eggplant, cucumbers
Direct seed or transplant: Kale, spinach, lettuce, radishes, carrots, arugula
Tasks: Soil warming, early transplants, aggressive succession planting
Summer
Grow: Tomatoes, peppers, cucumbers, squash, beans, basil
Watch for: Overheating — use roll-up sides, shade cloth, and plenty of airflow
Tasks: Harvest often, remove diseased plants, prep space for fall planting
Fall
Direct sow: Spinach, kale, chard, Asian greens, turnips, cilantro
Transplant: Brassicas started in late summer (broccoli, cabbage, kohlrabi)
Tasks: Clear summer crops, amend soil, mulch, plant successions for winter
Winter
Harvest: Spinach, mache, arugula, claytonia, cold-stored carrots and beets
Don’t plant: Growth is too slow; rely on crops planted in late summer/fall
Tasks: Monitor moisture, open on sunny days to vent excess humidity
Crops like spinach, kale, and mache don't just survive winter — they sweeten in cold weather. These are the backbone of a cold-season greenhouse garden.
Succession Planting: The Key to Year-Round Abundance
Succession planting allows you to make the most of every square foot, all year long.
In spring, sow spinach or radishes first, then follow with heat-loving summer crops.
In late summer, sow fall crops as summer plants are removed.
In fall, time cold-hardy greens so they establish before daylength drops below 10 hours (the “Persephone Period”).
Use this rhythm:
Fast crops → summer crops → fall crops → winter harvest → spring again
By rotating crops this way, your greenhouse beds stay productive nearly 365 days a year — even if plants are only growing 9 or 10 months out of the year.
Tips for Managing an Unheated Greenhouse in Winter
Winter doesn’t have to shut things down — but it does require thoughtful management:
Layer protection: Add row cover or low tunnels inside the greenhouse to buffer overnight lows.
Ventilate smartly: Open on sunny days to prevent humidity and mold.
Mulch deeply: Straw or leaf mulch insulates roots and reduces watering needs.
Sow early: Cold-hardy crops must be well established before true winter sets in.
Expect slow growth from December through January in northern regions — but don’t underestimate the value of harvesting fresh spinach or arugula in February from plants sown back in September.
Planning Your Space by Season
Here’s an example of how to use a 10×20 or 12×24 Sunbow Greenhouse through the year:
SeasonKey UsesEarly SpringSeed starting, spinach harvest, early greensLate SpringTransplant tomatoes, plant basil & cucumbersSummerMaintain summer crops, prep fall spaceFallPlant kale, radishes, spinach for winterWinterHarvest & hold cold-hardy crops
With careful planning, that same space could yield fresh food in 10–11 months of the year, without artificial heating.
Final Thoughts: A Greenhouse Is a Year-Round Tool
At Sunbow, we don’t just build greenhouses — we build year-round food systems for real growers. Whether you’re in zone 6 or zone 9, designing a four-season plan can help you:
Grow earlier and later than your neighbors
Reduce grocery bills through fall and winter
Build a more resilient, productive homestead
And with a strong, American-made greenhouse that’s designed to handle real weather, you don’t need to rely on heaters or fancy climate systems. You just need good soil, smart crop choices, and a plan that follows nature’s rhythm.
