Last Updated on September 18, 2026
How Many Leeks per Square Foot?
9 leeks per square foot, in a 3 by 3 grid, 4 inches apart. That is the count on my square foot gardening chart. With leeks the real question is not just the count, it is whether that spacing leaves room to blanch a long white shaft, since that is what most of the plant’s value is.
The spacing pattern
| Per square foot | 9 leeks, in a 3 by 3 grid |
|---|---|
| Inches apart | 4 inches |
| 4 x 4 bed (16 squares) | up to 144 leeks |
| 4 x 8 bed (32 squares) | up to 288 leeks |
| 3 x 6 bed (18 squares) | up to 162 leeks |
Leeks are not in the Plan My Garden planner’s crop list yet, so this count is straight from my chart, not planner spacing. Treat the bed totals above as maximums for a full bed of nothing but leeks: most gardeners give leeks one or two squares alongside everything else. Run the math on your own bed with my square foot garden calculator, or see how a square or two of leeks fits into a full layout like the 4×4 raised bed garden layout.
Spacing versus a thick, blanched shaft
The whole point of a leek is the long white shaft, and getting one takes more than spacing math. University of Maryland Extension says to transplant leeks deeply to force a long, thick, blanched stem: dibble a hole 5 to 6 inches deep with a stick about an inch across, drop the transplant in without filling the hole, then let soil wash in on its own and pull more soil up around the stem as the plant grows. University of Massachusetts Extension describes the same idea done in a trench: set leeks in a trench 3 to 4 inches deep, gradually fill it in as they grow, then hill soil around the stems another 3 to 4 inches. Either method blocks light from reaching the buried part of the stem, which is what keeps it pale and mild instead of green and tough.
University of Minnesota Extension gives the same two options: set transplants at the bottom of a 6 inch furrow and fill it in gradually, or plant at normal depth and mound compost or soil around the plants several times through the season. Both extensions note that some varieties are bred to self-blanch and need little or no hilling. Wood Prairie’s Alto leek, below, is one of those, described as needing less cleaning than a trenched leek because the shaft blanches on its own.
Why 4 inches apart trades size for count
My chart’s 4 inches apart is tighter than what the extensions recommend for a full-size shaft. Minnesota puts standard spacing at 2 to 6 inches apart, noting that a close 2 to 4 inches works well if the leaves are set to grow into the row space rather than into each other. Maryland’s own spacing recommendation is 5 inches apart, and its own numbers show what one well-spaced leek produces: one seed or transplant yields one sheath 6 to 8 inches long and 1 to 2 inches wide. Packing 9 into a square at 4 inches apart sits inside the tight end of that range, so each plant has less root room and less light than it would at 5 or 6 inches. If plant count matters more than shaft size, plant the full 9. If a thick shaft matters more, use fewer per square and give each one closer to the 5 to 6 inch spacing the extensions describe.
A long season, harvested through cold weather
Leeks take a while to get there. Minnesota extension says most leeks need a long growing season of about 120 to 150 days, though some newer cultivars mature in as few as 90. Maryland extension puts the range at 70 to 120 days depending on the cultivar, and notes leeks are biennial but grown as an annual, planted from seed started indoors well before it ever goes in the ground. That long season pays off at the other end: Minnesota extension says leeks are fairly frost tolerant, so you can delay harvest until after the first few frosts, with temperatures as low as 20 degrees Fahrenheit not harming some varieties if you mound mulch around them for protection. Maryland extension adds that a heavy blanket of straw or leaves over the bed in fall lets you keep harvesting through the winter. Because this crop is not yet in the planner, there is no planting-window table here. Use the seed starting calendar to work backward from your last spring frost for starting seed indoors, and check Plan My Garden’s frost dates for your zip code’s actual dates.
Germination temperature
From my vegetable seed germination temperature chart:
| Minimum | 32°F |
|---|---|
| Optimum range | 65 to 85°F |
| Maximum | 95°F |
Seed
Wood Prairie carries organic Alto leek seed, a Bulgarian-style leek that is versatile enough to harvest young as a bunching leek or left to mature for a thicker shank, at 70 days. It is a summer type, not winter-hardy, so plan to harvest it before hard cold arrives. A packet of about 250 seeds plants a 25 foot row: organic Alto leek seed. Code PMG5 takes 5 percent off.
Quick questions
How many leeks fit in a 4×8 raised bed?
Up to 288 leeks at 9 per square, 4 inches apart. A 4×4 bed holds up to 144 and a 3×6 bed holds up to 162, but that is a maximum for a bed of nothing but leeks. Most gardeners plant a square or two, not a whole bed.
How do you get long white leek shafts?
Blanch the stem by keeping light off the buried part. University of Maryland Extension describes dibbling a deep hole and letting soil wash in, then hilling more soil up as the plant grows. University of Massachusetts Extension describes the same result from a trench that gets filled in gradually. Both block light from the stem, which keeps it pale and mild.
Does tighter spacing make leeks smaller?
It trades shaft size for plant count. The 4 inch spacing behind 9 per square is tighter than the 5 to 6 inches University of Minnesota Extension and University of Maryland Extension describe for full-size shafts. Fewer leeks per square with more room each will grow thicker.
How long do leeks take to mature?
About 70 to 150 days depending on the cultivar. University of Minnesota Extension says most leeks need 120 to 150 days, with some newer cultivars ready in 90, while University of Maryland Extension lists a 70 to 120 day range.
Can you harvest leeks in cold weather?
Yes. University of Minnesota Extension says leeks are fairly frost tolerant and harvest can be delayed until after the first few frosts, with some varieties unharmed down to 20°F if mulched. University of Maryland Extension says a heavy layer of straw or leaves over the bed lets you keep harvesting through winter.
Let the planner place them
Leeks are not on the planner’s crop list yet, but the rest of your square foot bed still benefits from one. Plan My Garden is free to start: enter your zip code, draw your beds, pick the crops you are growing, and it places each one at square-foot spacing and builds a planting schedule from your frost dates.
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