Growing Spinach: A Complete Profile
By Growing Home Greens Team · July 18, 2026
Spinach is one of the fastest, most cold-tolerant greens you can grow, direct-seeded a full month before your last frost, but it’s also quick to bolt once the weather warms, so the growing window is short and worth planning around rather than fighting.
Sowing it a month before your last frost
Sow seed directly outdoors as early as four weeks before your last frost; spinach germinates fine in cool soil that would rot most other seeds. At 40 days to maturity and a dense nine plants per square foot, it’s one of the fastest turnovers in the garden. Plan on succession sowing every couple of weeks if you want a steady harvest instead of one big flush.
Bolting and mildew, the two things that end a planting
Bolting (sending up a central flower stalk and turning bitter) is almost always a heat and daylength issue, not a care mistake; once temperatures push into the 75-80°F range, spinach is on borrowed time regardless of watering. Downy mildew shows up as yellow patches on top of the leaf with fuzzy gray growth underneath, especially in damp, humid stretches; resistant varieties help more than any spray at that point.
A fast crop that clears out before summer
Radish is a documented companion, maturing quickly alongside spinach without competing for space. See the full companion guide for spinach. Its short season and dense spacing make it a good candidate in the Garden Designer for filling a bed early and clearing out before a slower summer crop needs the room.
Companion planting guide for Spinach · Find your planting dates
Typically viable in USDA zones 2-10. Not sure your zone? Look it up by ZIP code.
Method: Direct sow: Direct-sow outside. Spinach doesn't transplant well, or doesn't need the extra time indoors.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Spinach plants fit per square foot?
Spacing: 9 per square foot (square-foot-gardening spacing). Mature height: 0.5-1 ft.
Soil & water: pH 6-6.5. well-drained. Amend with lime if soil pH falls below 6.
Varieties worth considering
- Space (F1): Rated by the seed company with high resistance across a wide range of downy mildew races (1-3, 5, 6, 8, 9, 11, 12, 14, 16, 19), a smooth-leaf, all-season type worth considering where downy mildew has been a recurring problem. (source)
- Bloomsdale Long Standing: An open-pollinated heirloom, savoyed rather than smooth-leaf, that Cornell's disease-resistance factsheet lists as resistant to Downy Mildew races 1-12, 14 and 15. The one to grow if you want to save your own seed, which the hybrid Space above doesn't let you do reliably. (source)
- Hammerhead (F1): A full-savoy type Johnny's rates at about 27 days, resistant to downy mildew races 1-12, 14-16 and 19 plus intermediate white rust resistance. Bred specifically for early spring, fall and winter sowing since it bolts quickly once the weather warms, the opposite job to a slow-bolt summer pick. (source)
Cited from the source shown next to each variety. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement.
Where to buy spinach seeds
As an Amazon Associate we earn from qualifying purchases. Some links on this page also go to other retailers we may earn a commission from as an affiliate, at no extra cost to you. We only recommend products with a genuine consensus of positive, independent reviews. See the sources cited on each item.
See it growing
Search YouTube for "growing spinach" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
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Growing Spinach: A fast, cold-loving green that bolts the moment it gets warm. Timing matters more than technique.
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