How far apart to plant basil
Space basil 12 inches apart. University of Maryland Extension sets plants 12 inches apart in rows 18 inches apart, and Utah State University Extension thins seedlings until the final stand is 12 inches apart. Large-leaf Genovese basil grows 3 to 4 feet tall, so Clemson Extension spaces it 2 feet apart. The square foot method fits 4 basil plants per square foot, per the UC Master Gardeners guide.
The calculator opens at 12 inches each way in a raised bed. Pick Genovese in the variety menu to switch to 24 inches.
How many basil plants fit a raised bed
| Bed | 12 in each way | Genovese, 24 in | Square foot method (4 per sq ft) |
|---|---|---|---|
| 4 × 4 ft | 16 | 4 | 64 |
| 4 × 8 ft | 32 | 8 | 128 |
| 3 × 6 ft | 18 | 3 | 72 |
| 4 × 12 ft | 48 | 12 | 192 |
The first two columns keep half a spacing clear at the bed edges, the way the calculator counts. The square foot count fills every square to the edge, so it is the most you could fit.
In a garden row at Maryland's 12 by 18 inches, a 10 ft row holds 10 plants. How much basil do you need? Utah State suggests 5 to 10 plants per person for fresh use and another 5 to 10 per person to dry or freeze, so a 4 × 4 ft bed at 12 inches covers fresh basil for two or three people.
Sowing and thinning
Sow seed 1/8 to 1/4 inch deep; Utah State covers it lightly and Clemson plants it 1/4 inch deep. Utah State thins seedlings to 3 to 4 inches apart first, then keeps thinning until plants stand 12 inches apart. Seed sprouts in 5 to 14 days: Clemson counts 5 to 10 days at 70 °F, and Utah State about 10 to 14 days in soil at 75 to 85 °F.
When to plant basil outside
Basil is tender. Maryland sows it only after all danger of frost has passed because it does not tolerate chilly weather, and Clemson waits until nights stay above 50 °F and days are consistently in the 70s before transplanting. Starting seeds indoors 4 to 6 weeks ahead gives you plants ready for that date; see when to start basil seeds for dates by ZIP code.
Harvest and pinching
Utah State starts harvesting when plants have 6 to 8 leaves, cutting the stem back so 2 to 4 leaves remain. Maryland pinches stems as they lengthen to keep plants bushy, and says leaves can be picked about 6 weeks after planting. Utah State also suggests sowing basil every other week, which keeps young plants coming before older ones flower.
Basil grows well in pots, which Utah State recommends to save space; water and feed potted plants regularly. To combine basil with tomatoes and other crops, lay the bed out in the raised bed planner or the square foot gardening calculator.