Last Updated on October 9, 2026

Seed Planting Depth Chart for Vegetables

Plant a seed about twice as deep as it is wide. For most vegetables that works out to 1/4 inch for tomato, pepper and eggplant, 1/2 inch for spinach, radish and the cabbage family, and about 1 inch for beans, peas, corn and squash. Seeds that need light, like lettuce and dill, go on the surface, pressed in. In heavy clay soil, stay shallow.

The rule of thumb comes from University of Minnesota Extension: plant a seed two times as deep as its width, deep enough that one more seed could sit directly on top of it. A seed 1/8 inch wide goes about 1/4 inch down. The chart below gives the depth for each crop in inches, so you do not have to measure seeds.

Seed depth chart: seeds you start in trays

These are the crops the Plan My Garden planner starts indoors. Virginia Cooperative Extension says its depth guidance applies to seeds planted inside and out, so use the same depth in a tray or cell as you would in the garden.

Seed depth chart: seeds you sow in the garden

These are the crops the planner direct sows. Where two extension charts disagree, both numbers are shown. Use the shallower one in heavy soil and the deeper one in sandy or loose soil.

Seed depth chart: corn and vine crops, tray or garden

The planner gives these a short indoor start. Colorado State University Extension notes that vine crop roots are extremely intolerant of being disturbed and do best direct seeded; if you do transplant cucumbers, squash or melons, use young plants no more than 2 to 3 weeks from seeding. Big seeds, so about an inch deep either way.

Key: CSU is the planting depth column in Colorado State University Extension’s Vegetable Planting Guide (GardenNotes #720). UMaine is the depth column in University of Maine Cooperative Extension’s Planting Chart for the Home Vegetable Garden. VCE is Virginia Cooperative Extension’s Seed for the Garden. ISU is Iowa State University Extension’s germination table: L means press in and do not cover, L-D means lightly cover, and D means cover, usually 1/4 to 1/2 inch with the precise depth on the packet. Planner weeks are from the Plan My Garden planner and count from your last frost date. Sources do not fully agree on how deep is deep, which is why some rows above show two numbers; go with the shallower one in heavy soil.

How to get the depth right

In trays and cells. Fill each cell with mix, make an indent in the center with a pencil and plant two seeds in it, following the depth on the packet. In soil blocks, the block maker leaves a small divot for the seed. Cover the seeds with fine vermiculite and spray the tops with water; the vermiculite keeps the seeds moist. In open flats, UNH Extension makes furrows 1/8 to 1/4 inch deep for medium to large seeds and covers them lightly with vermiculite or sifted mix.

In the garden. Make a furrow or hole of the right depth, drop the seed in and draw soil back over it. Virginia Cooperative Extension says to firm the soil so it is in direct contact with the seed, which helps the seed take up moisture and sprout sooner, then water it in. For bush beans, plant nine per square foot in 1-inch deep holes and keep the soil moist for the first five to seven days until they germinate.

Light seeds. Iowa State’s table marks lettuce and dill as needing light: press them onto the surface and do not cover them. Celery and onion are marked lightly cover, so keep them as close to the surface as you can. For light-needing seeds in trays, University of Minnesota Extension uses a thin layer of fine vermiculite, porous enough to let light through while keeping the mix moist.

Heavy soil, sandy soil and summer sowing

The chart numbers are a middle setting. Virginia Cooperative Extension adjusts depth to your soil and the season:

• Heavy clay or silt: cover seeds only two to three times their diameter. After sowing, lay a band of sand, fine compost or vermiculite about 4 inches wide and 1/4 inch thick along the row. It holds moisture and reduces crusting, so seedlings push through more easily.
• Sandy soil or soil high in organic matter: seeds may be planted deeper, because seedlings emerge easily from loose soil.
• Midsummer sowing for fall: the soil is warm and dry, so cover seeds six to eight times their diameter and water them every day if needed. A shallow mulch or a board laid over the row until the seeds sprout also holds moisture.

The board trick works in spring too. Carrots have to stay moist while they germinate, so after I sow them I give them a good watering and shield the row with a board to keep it from drying out. Once they sprout, the board comes off.

Depth done, dates next

Depth is half of sowing. The other half is the date, and that comes from your last frost. Look yours up with the Plan My Garden frost date lookup, then count the weeks on my seed starting calendar. Cold soil also slows germination, so check the vegetable seed germination temperature chart before an early sowing, and see the 10 crops you can direct sow before your last frost.

Quick questions

How deep should you plant seeds?

About twice as deep as the seed is wide, deep enough that one more seed could sit on top of it, according to University of Minnesota Extension. Virginia Cooperative Extension says most vegetable seeds end up 1/4 to 1/2 inch deep, with big seeds like beans, corn and squash at 1 inch or deeper. Seeds that need light, such as lettuce and dill, are pressed onto the surface and not covered.

How deep do you plant tomato seeds?

1/4 inch. Colorado State University Extension lists 1/4 inch for tomato, pepper and eggplant seed. The Plan My Garden planner starts tomatoes indoors 5 to 3 weeks before your last frost.

How deep do you plant bean seeds?

About 1 inch. The University of Maine planting chart says 1 inch for snap and pole beans, and Colorado State says 1 to 1 1/2 inches. Plant bush beans nine per square foot in 1-inch deep holes.

Should you plant seeds deeper or shallower in clay soil?

Shallower. Virginia Cooperative Extension covers seeds only two to three times their diameter in heavy silt or clay soil, and suggests a band of sand, fine compost or vermiculite about 4 inches wide and 1/4 inch thick along the row to reduce crusting. In sandy or loose soil, seeds can go deeper.

Do you plant seeds at the same depth indoors and outdoors?

Yes. Virginia Cooperative Extension says its depth guidance applies to seeds planted both inside and out. Soil and season still change it: shallower in heavy clay, deeper in sandy soil, and for midsummer sowings into warm, dry soil it covers seeds six to eight times their diameter.

Let the planner date every sowing

Plan My Garden is free to start: enter your zip code and it finds your frost dates, draw your beds, pick beans, carrots, tomatoes and everything else you want to grow, and it places each plant at square-foot spacing and builds a planting schedule (start indoors, transplant and direct sow dates) from your frost dates.

Related: How to Start Seeds Indoors · Soil Blocks for Seed Starting · Seed Viability Chart · Square Foot Gardening Chart