The rice modelled on this site is an upland variety -- no flooded paddy needed, per the crop database's own description. What it does need is a genuinely long, warm growing season, which is exactly why it struggles in cooler maritime climates without extra protection. Like wheat, oats and barley, it's a self-pollinating cereal, so cross-pollination is a minor concern rather than a real seed-saving risk.
Water need
Even without flooding, upland rice needs consistently moist soil through the season -- more demanding than wheat, oats or barley, though far less than a flooded paddy would require.
Calories at a glance
3,640 kcal/kg -- a genuine staple grain, in the same calorie league as wheat and oats (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 Storage
- Sow direct once the soil is genuinely warm. Sow direct once frost risk has passed and the soil has warmed -- upland rice needs a long, warm season from the very start to mature in time.
- Keep soil consistently moist, not flooded. Water regularly to keep the soil consistently moist through the growing season -- upland rice does not need or want a flooded paddy.
- Watch for a long, warm growing window. In cooler or shorter-season zones, use a polytunnel or a warm, sheltered site to stretch the effective growing season.
- Harvest once seed heads turn golden and dry. Cut seed heads once they've turned golden and dried down in the field, before birds or damp weather can take a share.
- Thresh, dry fully and store. Thresh to release the grain, dry it fully, then store dry -- properly stored rice keeps for years.
Sowing & Harvesting Calendar
Pick your zone under "Temperature Range by Month" above and this updates too. Rice is not viable outdoors in Boreal or Alpine zones -- there simply isn't a long enough warm season to work with.
Calories & Yield
Rice's unit is kg seed grain, so yield here is a multiplication ratio -- the same convention this site uses for wheat, oats and barley. Subtropical gives the best return, and maritime zones take a genuine hit from the shorter warm season.
| Climate Zone | Yield ratio | Calories per kg planted | Viability |
|---|---|---|---|
| Tropical / Humid | 30× | 109,200 kcal | Viable |
| Subtropical | 35× | 127,400 kcal | Viable -- best yield |
| Mediterranean | 25× | 91,000 kcal | Viable |
| Temperate Maritime | 4.8× | 17,472 kcal | Challenging (60% yield) |
| Temperate Continental | 20× | 72,800 kcal | Viable |
| Cool / Boreal | -- | -- | Not viable |
| Arid / Semi-Arid | 12× | 43,680 kcal | Viable |
| Highland / Alpine | -- | -- | Not viable |
Figures from the site's own crop database. The Maritime ratio already reflects the 60% yield penalty applied to challenging zones -- 8× raw becomes 4.8× actual, exactly matching the figure surfaced by this site's own calorie rankings tool.
Varieties Worth Knowing
Rice varieties differ hugely by region, but two stand out for home growers -- one a historic paddy variety, the other genuinely suited to dry, non-paddy growing. Both below are open-pollinated (OP), meaning seed saved from them breeds true and is worth keeping under this site's seed-saving approach; neither is an F1 hybrid.
Seed Saving -- Quick Guide
Rice is self-pollinating with very low crossing risk -- though its seed doesn't store as long as other grains, so it's worth growing out and refreshing more often.
SERVINGS, NOT DAILY CALORIES This works out plate-sized servings of rice 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 rice -- 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
The site's own crop data is direct on this: store dried grain for years.
Thresh, dry thoroughly and keep cool, dry and pest-proof -- rice is one of the most genuinely long-term storable staples this site models, alongside wheat and barley.
Growing Rice Without Bought Inputs
Because upland rice doesn't need a flooded paddy, it avoids the irrigation infrastructure that makes conventional rice growing so input-heavy -- a genuine advantage for a self-sufficiency setting.
Birds are the main threat to ripening seed heads, the same risk faced by quinoa and amaranth.
Netting over ripening heads and consistent watering through the season are simple, genuinely effective input-free measures.
Frequently Asked Questions
Do I need a flooded paddy to grow rice at home?
No -- the site models upland rice, which the crop database describes as not needing flooding at all. It's grown like any other cereal in ordinary garden soil, though it does need a genuinely long, warm growing season to reach harvest.
Why is rice challenging in maritime zones?
Because rice needs a long, warm season to mature, and cooler maritime summers cut that short without protection such as a polytunnel or a warm, sheltered site -- the yield figures below reflect that penalty directly.
Does rice cross-pollinate easily?
No -- like wheat, oats and barley, rice is self-pollinating and largely cleistogamous, meaning it fertilises itself before the flower even fully opens. Natural cross-pollination is typically under 1%, so isolation distance is a minor concern rather than a real risk.
How is rice yield measured on this site?
As a multiplication ratio rather than a per-plant weight, the same convention this site uses for wheat, oats and barley -- sow 1kg of seed grain and harvest that many times over, depending on your zone.
How long does stored rice grain keep?
The site's own crop data says dried grain stores for years -- kept cool, dry and pest-proof, rice is one of the most genuinely long-term storable staples this site models.