Farm tools
Know your farmBefore you commit
19 free farm tools on South African figures: Grain SA, SAFEX and the Land Bank. Pick one, type your own numbers.
Harvest date
When will my crop be ready?
1. Your crop
2. Your cultivar
Source: Grain SA, Pula Imvula: Harvesting at the right time is vital (R. McPherson, July 2021).
3. Heat units at the farm (optional)
The answer
Enter the date the crop was up (emergence).
How this works and the sources
From the day you planted, or the day the crop came up, and your cultivar's days to physiological maturity, the date the crop is ripe; then the drying days to harvest moisture as a range: the window in which the combine can roll. Your seed company's days for your cultivar come first; where you leave them out, the crop's published South African figure is used and named (Grain SA for maize, soybeans and sunflower, Pannar for grain sorghum). Wheat has no published figure we could read, so it needs your cultivar's days. For maize, the heat units too: Grain SA's formula on NASA POWER's temperatures for the town nearest the farm, anywhere in South Africa, or the farm's own coordinates.
What this does not tell you
- The days are counted, not the weather: a cool season makes the crop later, a hot one earlier. For maize the heat units help, but they are an average year (2001 to 2025) in a cell of about 50 km around the town or the farm, not this season and not the farm's own weather station.
- Heat units only for maize: Grain SA gives the base temperature (10 C) for maize; for soybeans, sunflower, sorghum and wheat we have no South African base temperature, so they count days only.
- A frost before maturity ends the season early; sorghum is very sensitive to it.
- Grain SA's 119 days for maize is one example; ultra-short to long cultivars differ by weeks. Enter your cultivar's days from the seed company.
- The harvest window is a range, not a date: the moisture of the grain on your lands and the limit of your silo decide. Walk the lands and test before you plan the combine.
- No agronomic advice: speak to your seed company or your adviser.
- Nothing you enter is uploaded or kept by us; the share link carries the crop, the date, the days, the town or the coordinates you typed and the heat units only. The towns and temperatures are read from our own site.
Sources
- Grain SA, Pula Imvula: Harvesting at the right time is vital (R. McPherson, July 2021) (2021-07-01)
- Pannar Seed, grain sorghum hybrids: days to harvest (2026-11-02)
- Grain SA, Pula Imvula: Using heat units and rainfall records to determine crop yield potential (March 2017) (2017-03-01)
- NASA POWER daily temperature at 2 m (MERRA-2), 2001 to 2025; towns: GeoNames (CC BY 4.0), https://www.geonames.org/ (2026-11-02)
Estimate, not advice. Confirm every figure with your bank, attorney and tax practitioner before a decision.