Plant Spacing Calculator
Free plant spacing calculator: find how many plants fit in any garden bed based on spacing requirements. Includes vegetable spacing guide and square f
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How to Calculate Plants Per Square Foot
The plant spacing calculator determines how many plants fit in a given area. "Plant spacing calculator" gets 2K monthly searches. For square spacing: Plants = Area (sq ft) / Spacing (ft)2. For triangular spacing (staggered rows, 15% more efficient): Plants = Area / (0.866 × Spacing2).
Examples: 100 sq ft bed with tomatoes needing 24" (2 ft) spacing. Square = 100/(22) = 25 plants. Triangular = 100/(0.866×4) = 29 plants. With 12" spacing: 100 plants (square) or 115 plants (triangular offset rows).
Square Foot Gardening — Plants Per 1-Foot Square
- 1 plant per sq ft (12" spacing): Tomatoes (staked), peppers, broccoli, cabbage, cauliflower, eggplant
- 2 per sq ft (8–9" spacing): Chard, large basil, dwarf kale
- 4 per sq ft (6" spacing): Head lettuce, spinach bunches, bush beans
- 9 per sq ft (4" spacing): Beets, garlic, turnips, spinach (intensive)
- 16 per sq ft (3" spacing): Radishes, green onions, baby carrots
- Vining crops (trellis): 1 plant per 3–4 sq ft. Cucumbers, pole beans grow vertically.
Vegetable Spacing Quick Reference
- Tomatoes: 18–36" in-row (det. 18–24", indet. 24–36"). Row spacing 36–48".
- Peppers: 12–18" in-row, 24–36" row spacing
- Cucumbers: 6–12" trellised, 12–24" ground. Rows 4–6 ft apart.
- Zucchini / Summer squash: 24–36" in-row, 36–48" rows. Large plants — never crowd.
- Lettuce (head): 10–12" spacing. Leaf lettuce: 4–6" for cut-and-come-again.
- Garlic: 4–6" between cloves, 6–12" between rows
- Corn: 9–12" in-row, 24–36" row spacing. Plant in blocks of 4+ rows for wind pollination.
- Carrots: Sow 1/2" apart, thin to 2–3" final spacing after germination
- Onions: 4–6" for bulbing onions; 2–3" for green onions/scallions
- Potatoes: 12" in-row, 30–36" row spacing. Plant seed pieces with eyes up.
Flower and Perennial Spacing Guide
- Annual flowers (petunias, marigolds, impatiens): 8–12" spacing. A 4×4 ft bed = 12–25 plants.
- Perennial flowers (coneflower, daylily, black-eyed Susan): 18–24". Space to allow for 2nd/3rd year spreading.
- Foundation shrubs: Space = (Mature Width Plant A + Mature Width Plant B) / 2
- Privacy hedge: Plant 2–3 ft apart for fast coverage; shrubs will fill in within 2–3 growing seasons.
Frequently Asked Questions About Plant Spacing
What happens if plants are too close together?
Overcrowding causes: competition for water and nutrients reducing individual plant yield, reduced air circulation leading to fungal disease (powdery mildew, early blight), difficulty weeding and applying targeted treatments, and root-bound conditions in containers. For tomatoes specifically, overcrowding is a primary driver of early blight — leaves touching neighboring plants spread spores rapidly. Better to grow 6 well-spaced, productive plants than 12 crowded, disease-prone ones.
Can I space plants more closely in a raised bed?
Yes, by 10–20%. Raised beds with quality amended soil — excellent drainage, high organic matter, and regular fertilization — can support slightly tighter spacing. The key is maintaining soil fertility: intensive spacing demands frequent compost additions and fertilizing because plants exhaust nutrients faster. Square foot gardening guidelines are calibrated specifically for raised beds with premium soil; they should not be applied to in-ground rows with native soil without amendment.