Crop Planning calculators

Start from the two hard limits — climate and soil. Use the Best Crop for My Climate tool to rank crops against your temperature, rainfall and frost-free days, then the Best Crop for My Land tool to filter by soil texture, pH and drainage. A crop that scores well on both, fits your sowing window and has a market is the right pick.

Seed rate = (target plants/ha × thousand-grain weight in g) ÷ (germination % × purity % × establishment %) ÷ 100, in kg/ha. Typical rates: wheat ≈ 100 kg/ha, rice (transplanted) ≈ 20–25 kg/ha, maize ≈ 20 kg/ha, soybean ≈ 60–75 kg/ha. The Seed Rate and TGW Seed Rate calculators do the maths and adjust for your lot's germination and purity.

The optimum population balances per-plant yield against plants per area — too thin wastes land, too dense causes competition and lodging. Triangular (hexagonal) spacing fits about 15.5% more plants than square at the same plant-to-plant distance. Use Plant Spacing & Population to convert any row × plant spacing to plants/acre and seeds to buy.

GDD = average daily temperature minus the crop's base temperature, accumulated day by day. Crops reach each stage at a fixed GDD total rather than a fixed number of calendar days, so GDD predicts maturity far better than the calendar in a warm or cool year. Maize, for example, needs roughly 1,400–1,700 GDD (base 10°C) to black layer.

Back-calculate: target harvest date minus the variety's days-to-maturity (plus nursery days for transplants) gives the sow-by date. The Planting Date and Days to Harvest calculators do this both ways, and the Frost Date tool checks the crop still finishes before the first autumn frost.

Rotating families breaks pest and disease cycles, and a legume in the rotation can leave 20–60 kg N/ha of nitrogen credit for the next crop, cutting fertiliser cost. The Crop Rotation Planner suggests what to plant next, and the Nitrogen Credit Planner rolls those credits forward across a 3–4 year sequence.

Transplanting gives a head start, weed advantage and uniform stand but costs nursery time and labour; direct seeding is cheaper and faster to establish but needs good seedbed moisture. The Transplant vs Direct-Seeding tool compares net margin, cost, time-to-harvest and water saved so the deciding factor is explicit for your numbers.

Place 100 seeds (4 reps of 25) on moist paper at the crop's ideal temperature, count normal seedlings after the standard days, and divide by the seeds set. Germination below ~85% for cereals usually means raising your seed rate or replacing the lot. The Seed Germination Test tool turns the count into a % and an adjusted seed rate.

Temperate fruit need accumulated winter chill (commonly hours below 7°C) to break dormancy and flower evenly — apple often 800–1,200 hours, peach 400–1,000, low-chill varieties under 300. Use Chilling Hours, Chill Units (Utah) or Chill Portions (Dynamic) to check your area meets a variety's requirement.

Land Equivalent Ratio (LER) is the land you'd need as sole crops to match what an intercrop yields together; LER above 1.0 means the intercrop is more land-efficient. A maize+legume intercrop often reaches LER 1.2–1.4. The Intercropping LER tool also shows the money advantage and land saved.

1 hectare = 2.471 acres = 10,000 m²; 1 acre = 0.405 ha = 43,560 ft²; 1 acre ≈ 100 cents ≈ 40 guntha. Bigha varies by region (often 0.25–0.40 ha). The Land Area Calculator converts all of these and also computes a plot's area from its shape.

Yield follows a plateau curve around the optimum population: a stand 20–30% below optimum can lose 10–20% of yield, while over-dense stands invite lodging and disease with little yield gain. The Plant Population Yield Response tool estimates your yield as a percent of potential from how far your stand sits off optimum.