How to Plant: A Foolproof Guide for Seeds, Seedlings, and Transplants
"How to plant" sounds simple until you're holding a seed packet wondering whether 1/4 inch deep means something specific, or staring at a tomato seedling unsure how deep to bury the stem. The good news: a handful of rules cover the vast majority of what you'll ever plant.
Planting Seeds Directly
The general rule for seed depth: plant a seed roughly 2-3 times as deep as the seed is wide. Tiny seeds like lettuce need barely any soil covering them; large seeds like beans or squash need about an inch.
- Tiny seeds (lettuce, carrots): press lightly into soil surface, barely cover.
- Small seeds (radish, spinach): 1/4 to 1/2 inch deep.
- Medium seeds (beans, peas): 1 inch deep.
- Large seeds (squash, cucumber): 1-1.5 inches deep.
Keep soil consistently moist (not soaked) until germination — this is the single most important factor for seed success.
Planting Transplants and Seedlings
Most vegetable transplants (tomatoes, peppers, lettuce starts) should be planted at the same soil depth they were growing in their container — with one major exception: tomatoes. Tomato seedlings can be buried deeper, up to the first set of leaves, because they grow roots along the buried stem, creating a stronger root system.
Spacing: Why It Matters More Than People Think
Crowded plants compete for light, water, and nutrients, leading to weaker growth and more disease pressure from poor airflow. Always check the seed packet or plant tag for spacing — but as general guidance:
- Leafy greens: 6-12 inches apart
- Bush beans: 4-6 inches apart
- Tomatoes/peppers: 18-24 inches apart
- Squash/cucumbers: 24-36 inches apart (they sprawl)
Timing: Planting at the Right Moment
Know your last frost date and work backward. Cool-season crops (lettuce, peas, spinach) can go in 2-4 weeks before your last frost. Warm-season crops (tomatoes, peppers, squash) should wait until after all frost risk has passed and soil has warmed.
For a full crop-by-crop timeline from planting to harvest, see our guide on how long it takes for each planter to grow. And if you're planting trees or shrubs rather than vegetables, our landscapes and trees guide covers planting depth specific to woody plants.
Frequently Asked Questions
A general rule is 2-3 times as deep as the seed is wide — tiny seeds barely covered, large seeds like beans about an inch deep.
Tomato seedlings can be planted deeper than other transplants, up to the first set of leaves, since they grow extra roots along the buried stem.
Seeds planted too deep often fail to germinate or emerge weak, since they exhaust their stored energy before reaching sunlight.
Check your local last frost date — cool-season crops can go in a few weeks before it, while warm-season crops should wait until after it has passed and soil has warmed.