Seed Spacing Calculator
Select a crop and enter your row length to get seeds needed plus planting tips.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
Can't find what you need?
Request a ToolHow to Use the Seed Spacing Calculator
This calculator tells you how many seeds to buy for common vegetable crops based on your row length and number of rows. It also shows the recommended spacing and sowing depth for each crop. Here is how to use it:
- Select your crop. Choose from tomato, pepper, lettuce, carrot, bean, cucumber, squash, or corn. Each crop has pre-set spacing and seeding rate data based on standard gardening recommendations.
- Enter your row length. Measure the length of one row in feet. For a 4x8 raised bed, you might have 8-foot rows. For an in-ground garden, rows can be as long as your space allows.
- Set the number of rows. Enter how many rows of this crop you are planting. If you want one row of carrots, enter 1. For a full bed of carrots, enter the number of rows that fit at the appropriate spacing.
- Buy your seeds. Seed packets list seed counts. Use the total from this calculator to make sure you have enough, with a few extra for poor germination or thinning.
About the Seed Spacing Calculator
Seeding rates vary widely by crop. Carrots are direct-sown densely at 6-8 seeds per foot because germination is unreliable and seedlings must be thinned. Tomatoes and cucumbers are spaced 24-48 inches apart with just one or two seeds per planting spot. This calculator uses average seeds-per-foot rates to give you a realistic seed count including extras needed for thinning and germination losses.
Sowing depth is just as important as spacing. Seeds planted too deep may not germinate. Seeds planted too shallow may dry out before rooting. The depth figures in this calculator follow standard planting guides: fine seeds like lettuce need just a dusting of soil, while beans and corn are planted an inch deep.
Frequently Asked Questions
How far apart should I plant carrots?
Carrot seeds should be sown 2-3 inches apart in rows 6-12 inches apart. Because carrot germination can be spotty, it is common to sow seeds more densely (6-8 per foot) and then thin seedlings to 2-3 inches when they are about 2 inches tall. Thinning is critical for proper root development. Crowded carrots produce small, forked, or stunted roots. Thin by snipping with scissors rather than pulling, to avoid disturbing neighbors.
Why does corn need to be planted in blocks?
Corn is wind-pollinated. The tassel at the top of the plant releases pollen that must land on the silks of other corn plants. A single row of corn rarely pollinates well because most pollen blows past with no silks to catch it. Planting in blocks of at least 4 rows (or a minimum of 16 plants in a 4x4 square) ensures that pollen falls on nearby silks. Poor pollination results in ears with missing or sparse kernels.
How many tomato seeds should I start indoors?
Start 2-3 seeds per cell or pot to ensure at least one germinates. Tomatoes typically germinate at 75-90% in good conditions, so 2 seeds per spot gives you excellent odds. After germination, thin to one seedling per cell by snipping the weaker ones at soil level. Start seeds 6-8 weeks before your last frost date. Each cell produces one transplant, so start as many cells as the number of plants you plan to put in the garden.
What does sowing depth mean?
Sowing depth is how deep below the soil surface you place the seed before covering it. As a general rule, seeds should be planted at a depth of 2-3 times their diameter. Very fine seeds like lettuce, carrots, and celery need only a light dusting of soil (less than 1/4 inch). Medium seeds like beans and corn are planted 1 inch deep. Large seeds like squash and cucumbers go about 1/2 to 1 inch deep. Planting too deep prevents light from reaching germinating seeds that need it, while planting too shallow exposes seeds to drying out.