Radish is the fastest crop on this site -- some varieties ready in as little as three weeks -- and its real value for self-sufficiency is filling short gaps in a rotation with almost no time committed, not calories. Botanically it's a different genus from swede and turnip despite the family resemblance, so it doesn't cross with either. Mouli and daikon types give radish a second, slower role too: a genuine winter-storage root, not just a quick salad crop.
Water need
Quick to bolt or turn woody under any real dry spell -- consistent moisture matters even for a crop this short-lived.
Calories at a glance
160 kcal/kg -- the lowest of any crop covered on this site so far (scale is log-based across all 55 crops in the calculator).
Temperature Range by Month
Month on the bottom, temperature up the side. The pale green background is what the plant can survive at all -- fatal above or below it, labelled directly on the chart where that applies to your zone. The coral band is its ideal range, and only fades in during the months this zone would actually have the crop in the ground -- reusing the exact same sowing/harvesting data as the calendar further down the page. The blue line is real monthly climate data (not a modelled estimate) for a representative rural/agricultural location in this zone -- a small farming town or agricultural research station rather than a major city, to avoid the warmer bias city weather stations have. For the actual verdict on how well this crop does in your zone, see the badge at the top of the page -- that's based on the site's own researched yield figures, not this chart.
Quick Start: Sowing to Harvest
- Sow direct, little and often. Sow direct, thinly, every 1-2 weeks through your zone's sowing window -- short rows sown often beat one long row sown once for a steady supply.
- Thin promptly. Thin seedlings as soon as they're large enough to handle -- crowded radish stays small and bolts faster.
- Keep watering even. Radish is quick to bolt or turn woody under any real dry spell, so consistent moisture matters even for a crop this short-lived.
- Pull salad types young. Standard radish is best pulled small and eaten fresh -- leaving it too long, especially in warm weather, makes it pithy and overly sharp.
- Grow mouli/daikon types for storage. For a winter-storage crop, choose a mouli or daikon variety, let it size up fully, then lift and store it like carrot or beetroot in damp sand in a cool shed.
Sowing & Harvesting Calendar
Pick your zone under "Temperature Range by Month" above and this updates too. The Sow row: green is the normal safe sowing window, amber is pushing the season by roughly a month either side, blue is an even earlier under-glass start. Radish has the widest sowing window of any crop on this site, wide enough for many successive batches within it. The Harvest row shows the main harvest window -- radish doesn't get the striped living-larder tail some other root crops here do, since it's better lifted and, for mouli/daikon types, stored rather than left in the ground.
Calories & Yield
Radish is the lowest calorie density crop covered on this site at about 160 kcal per kg. Subtropical and Mediterranean zones give the best yields here -- but with a crop this fast, total output per year from repeated sowings matters far more than any single yield figure.
| Climate Zone | Yield per plant | Calories per plant | Viability |
|---|---|---|---|
| Tropical / Humid | 0.05 kg | 8 kcal | Viable |
| Subtropical | 0.08 kg | 12.8 kcal | Viable -- best yield |
| Mediterranean | 0.08 kg | 12.8 kcal | Viable -- best yield |
| Temperate Maritime | 0.07 kg | 11.2 kcal | Viable |
| Temperate Continental | 0.07 kg | 11.2 kcal | Viable |
| Cool / Boreal | 0.05 kg | 8 kcal | Viable |
| Arid / Semi-Arid | -- | -- | Not viable |
| Highland / Alpine | 0.05 kg | 8 kcal | Viable |
Figures per plant sown, from the site's own crop database. Mouli/daikon types are individually larger, but the figures above reflect the standard salad radish this database models.
Varieties Worth Knowing
Radish varieties split into fast summer salad types and slower, pungent winter storage types -- worth having one of each rather than treating radish as a single crop. All the varieties below are open-pollinated (OP), meaning seed saved from them breeds true and is worth keeping under this site's seed-saving approach; none are F1 hybrids.
Seed Saving -- Quick Guide
Radish is self-incompatible -- a single plant can't pollinate itself, so you need several plants flowering together just to get seed at all -- and it crosses readily with wild radish, a common arable weed.
SERVINGS, NOT DAILY CALORIES This works out plate-sized servings of radish from your seed during its fresh harvest window only, not your group's full daily calorie needs. For that, use the main calculator.
Estimated for your selected zone above, using this site's own germination, loss and yield figures for radish -- a helping is roughly what you'd put on a plate as part of a meal with other veg. Treat it as a planning estimate, not a promise.
Storage & Preservation
Unlike swede, parsnip, celeriac and salsify, radish isn't described as a living larder in the site's own crop data -- standard salad radish is best pulled and eaten fresh within days of reaching size.
For a genuine winter-storage crop, grow mouli or daikon types instead: let them size up fully, then lift, trim the tops, and store the unwashed roots in slightly damp sand in a cool shed or cellar, the same way as carrot or beetroot.
Growing Radish Without Bought Inputs
Flea beetle is the main pest to watch for -- it riddles young leaves with small holes and can check growth badly on a crop this fast-growing, since there's little time to recover before harvest.
Fine mesh or fleece from sowing onward is the simplest input-free defence -- it physically excludes the adult beetle before it can lay eggs, and matters more here than on slower crops since radish has so little growing time to spare.
Radish is sometimes used as a trap crop for flea beetle to draw pressure away from slower, more valuable brassicas nearby -- a useful role in a wider input-free growing plan, though it means expecting some damage on the radish itself.
Frequently Asked Questions
How fast is radish really?
The fastest crop on this site -- some varieties are ready in as little as 3 weeks. That speed is its real value: short successive sowings from March to September keep a continuous supply coming with very little space or time committed at once.
What are mouli or daikon radishes, and why grow them?
Larger, longer-rooted radish types bred for storage rather than quick eating -- where a standard salad radish is pulled within weeks, mouli/daikon types are left to size up and then stored like a root vegetable, giving radish a genuine winter-storage role alongside its usual quick-crop one.
Does radish cross-pollinate with swede, turnip or the other brassicas on this site?
No -- radish (Raphanus) is a different genus from swede and turnip (Brassica) and from the kale/cabbage/broccoli/cauliflower/Brussels sprouts/kohlrabi group (also Brassica). None of them cross with radish.
What does radish actually need isolating from, then?
Other radish varieties, and wild radish (Raphanus raphanistrum) -- a common weed that readily crosses with the cultivated crop. If wild radish grows nearby, remove flowering plants before they set seed, the same precaution as wild carrot or wild salsify elsewhere on this site.
How cold and hot can radish survive?
Roughly -3°C to 24°C, with ideal growth in the 10-21°C range. Radish tolerates light frost reasonably well but is quick to bolt in heat above roughly 24°C, sending energy into flowering instead of the root -- a real risk for a crop this fast-growing.
Is radish a good calorie crop for self-sufficiency?
No -- at around 160 kcal per kg it's the lowest-calorie crop covered on this site. Its value is speed, succession cropping and filling short gaps in a rotation, not calories on their own.