Garden PlannerEvidence-aware. Garden with confidence.

Garden Calculators

Turn measurements and growing goals into practical garden quantities.

Plant Spacing & Quantity

Calculate how many plants fit in your bed at a chosen spacing.

Recommended for tomato: 18–24 in

Planning & Layout

Bed AreaCalculate area of beds by shape and size.
sq ft
Plant QuantityHow many plants fit based on spacing.
plants
Row SpacingPlan row spacing for seeds or transplants.
in

Seeds & Sowing

Seed Starting DateFind ideal start dates by last frost date.
date
Succession IntervalPlan repeat plantings for steady harvests.
days
Seed NeededEstimate seed amount based on plants.
seeds

Soil & Amendments

Soil VolumeCalculate soil volume for beds or containers.
cu ft
Compost AmountEstimate compost to mix into existing soil.
cu ft
Mulch VolumeCalculate mulch needed to a set depth.
cu ft

Water & Irrigation

Watering EstimateEstimate water needs for your garden.
gal
Drip Line LengthMeasure drip line needed for layouts.
ft

Harvest & Storage

Expected HarvestEstimate harvest by plant count.
lb
Storage CapacityEstimate storage needs for root crops.
cu ft

About these calculators

Our calculators use research-based formulas and agronomic guidelines from trusted university extension sources and peer-reviewed literature. They are designed to help you plan with confidence—not to replace your experience.

Key sources & assumptions

  • Spacing and planting recommendations: Cornell, OSU Extension, RHS
  • Water: 25 mm/week target from extension guidance; adjust for soil and heat
  • Soil and amendments: volume arithmetic; mix ratios are common practice, not prescriptions
  • Values vary by variety, climate, soil and management

About results

Results are estimates based on the information you provide. Actual results will vary with weather, soil, varieties and growing conditions. Use calculations as a starting point, then observe and adjust as you garden.

Last updated
Aug 26, 2026

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Our Methodology & Sources

We synthesize peer-reviewed research, university extension publications, and trusted horticulture resources. Our evidence levels help you understand how strong the science is behind the guidance.

Evidence tiers

Supported evidenceConsistent results from multiple robust studies
Traditional claimHistorical use reported, limited scientific support
Context dependentMixed or variable results across conditions
No verified relationshipNo reliable evidence identified

Primary source types

  • Peer-reviewed journal articles
  • University extension publications
  • Government & research institute reports
  • Systematic reviews & meta-analyses

Last updated

August 24, 2026

Learn more about our approach