A genuinely long-season crop -- sown in spring for a harvest that doesn't really get going until autumn and then keeps producing right through winter, picked progressively up the stalk rather than all at once. Frost doesn't just fail to hurt it, it actively improves the flavour, which makes this one of the more reliable sources of fresh vitamin C through the coldest months. It also has a real edge over its brassica relatives when it comes to seed saving, covered below.
Water need
Roughly 25-38mm (1-1.5in) a week, rising to about 50mm (2in) in hot, dry weather.
Calories at a glance
420 kcal/kg -- the highest of the common brassicas grown here, though still low compared to true calorie staples like potatoes or dried beans (scale is log-based across all 55 crops in the calculator, staples included).
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. Sow Mar-Apr -- this is a long-season crop, so getting it started on time matters more than with faster brassicas. Check the calendar below for your zone.
- Transplant & firm the soil well. Move seedlings out once well-rooted and firm the soil down hard around each one. Loose ground is the single biggest cause of loose, leafy sprouts instead of tight ones.
- Tend through the season. Water consistently and stake tall stalks if your site is windy -- wind rock loosens the roots and affects sprout quality. Removing yellowing lower leaves as sprouts below them mature improves airflow and access.
- Start picking from the bottom. Begin harvesting once the lowest sprouts are firm and about walnut-sized, working up the stalk as more mature above them. This typically starts several months after sowing and continues over an extended period.
- Keep picking through winter. Frost actually improves the flavour by converting stored starches to sugars, so keep working up the stalk right through cold weather rather than clearing the plant early.
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 with basic outdoor protection (cold frame, fleece, cloche), blue is starting seed indoors or under glass for an even earlier transplant. The Harvest row has two shades: solid green is the crop database's own harvest window, already several months wide since sprouts mature progressively, while the striped tail is picking further up the stalk as the season allows, right up to whenever you'd next sow. Where that carries on past December, the calendar keeps going into a second year rather than cutting it off.
Calories & Yield
Brussels sprouts sit a step above the rest of this brassica cluster on calories -- about 420 kcal per kg, noticeably more than broccoli, cauliflower or cabbage, though still well short of true calorie staples. Combined with its long storage life and hardiness, it's one of the more genuinely useful winter brassicas rather than purely a nutrition crop.
| Climate Zone | Yield per plant | Calories per plant | Viability |
|---|---|---|---|
| Tropical / Humid | 0.5 kg | 210 kcal | Viable |
| Subtropical | 0.6 kg | 252 kcal | Viable |
| Mediterranean | 0.6 kg | 252 kcal | Viable |
| Temperate Maritime | 0.6 kg | 252 kcal | Viable |
| Temperate Continental | 0.6 kg | 252 kcal | Viable |
| Cool / Boreal | 0.4 kg | 168 kcal | Viable |
| Arid / Semi-Arid | -- | -- | Not viable |
| Highland / Alpine | 0.3 kg | 126 kcal | Viable |
Figures per plant sown, from the site's own crop database. Like winter cabbage, Brussels sprouts isn't viable in Arid zones at all -- it needs a real cold season to do what it does. Subtropical, Mediterranean, Maritime and Continental all tie for the highest yield.
Varieties Worth Knowing
Brussels sprouts have fewer named heirlooms in wide circulation than most brassicas, since the crop has been heavily bred as F1 hybrids commercially -- these are the well-established OP exceptions. 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
Brussels sprouts cross freely with kale, broccoli, cauliflower, cabbage and kohlrabi -- all one species (Brassica oleracea). It's biennial, needing a full cold winter before reserved plants will flower and set seed.
SERVINGS, NOT DAILY CALORIES This works out plate-sized servings of Brussels sprouts from your seed during its fresh harvest window only, not your group's full daily calorie needs. For that, use the main calculator.
BIENNIAL Brussels sprouts are a biennial, not an annual -- they don't produce seed in their first year. Plants grow through year one, a few overwintered plants flower and set seed in year two, and that seed is only ready to sow in year three. If you're starting from scratch with no ongoing seed supply, that means having enough seed on hand for both year one's and year two's sowing up front. Plan for roughly double the seed quantity below if that's your situation.
Estimated for your selected zone above, using this site's own germination, loss and yield figures for Brussels sprouts -- 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
Once picked, Brussels sprouts keep about 4-10 weeks in cool conditions depending on climate zone, similar territory to cabbage and well ahead of broccoli or cauliflower. They keep noticeably longer left attached to a cut section of stalk than picked loose, if you have the cool storage space to do it that way.
For longer preservation, blanch and freeze works well and holds texture reasonably. They can also be fermented or pickled, though this is less traditional for sprouts than it is for cabbage.
Growing Brussels Sprouts Without Bought Inputs
Brussels sprouts share the same pest profile as the rest of the brassica family -- cabbage white caterpillars, flea beetle, aphids -- and exactly which one causes trouble depends heavily on where you are. What works almost everywhere instead:
Floating row covers or fine insect netting are the single most effective input-free defence while plants are young -- they physically exclude the large majority of common brassica pests, with no identification needed.
Companion planting helps too: aromatic herbs like dill, oregano or thyme interplanted nearby mask the scent brassica pests use to find their host, and nasturtiums nearby often draw pests away as a sacrificial trap crop.
Crop rotation matters as much as pest defence -- avoid growing any brassica in the same bed two years running. This breaks the life cycle of soil-borne problems like clubroot, which can persist in soil for years without a host to reset the clock.
Firm planting is this crop's biggest zero-input lever specifically -- treading the soil down well around each transplant costs nothing and is the main thing standing between tight, firm sprouts and loose, leafy ones.
Frequently Asked Questions
Can I eat Brussels sprouts and still save seed from the same plant?
Yes -- uniquely among this brassica cluster. The sprouts you eat grow in the leaf joints down the stalk, separate from the growing tip at the top that goes on to flower the following spring. Pick the lower sprouts as normal and simply leave the plant standing (don't cut it down) to let the top flower for seed in year two.
Can I save seed if I'm also growing broccoli, cabbage or kale?
Only carefully. Brussels sprouts can cross-pollinate with kale (oleracea-type), broccoli, cauliflower, cabbage (summer and winter/Savoy), kohlrabi and purple sprouting broccoli if more than one is left to flower nearby at the same time. Keep varieties about half a mile (800m) apart for home use, or only let one flower per season.
How cold can Brussels sprouts survive?
Reliably down to about -4°C (25°F), the formally verified baseline. Grower sources report well-hardened plants surviving down to around -9°C (15°F), with a few late varieties tolerating a little more -- but that figure comes from field experience rather than controlled trials, so treat it as a reasonable extreme rather than a guarantee. Ordinary frost is actively good for the crop either way.
Why are my sprouts loose and leafy instead of tight and firm?
Almost always loose soil. Brussels sprouts need the soil firmed down well at planting -- in loose ground the plant puts energy into leafy, open ("blown") sprouts instead of tight ones. Firm planting and staking tall stalks against wind rock both help.
How long do they keep after picking?
About 4-10 weeks in cool conditions depending on climate zone, similar to cabbage. They keep noticeably longer left attached to a cut section of stalk than picked loose, if you have the space to store it that way.
Is it a good calorie crop for self-sufficiency?
Better than most of its brassica relatives but still not a staple -- about 420 kcal per kg, noticeably higher than broccoli, cauliflower or cabbage, though well below true calorie crops like potatoes or dried beans. Worth growing for its combination of nutrition, storage life and hardiness.
How long does the seed stay viable?
Around 4-5 years if kept cool, dark and dry, similar to other Brassica oleracea seed, though germination rates decline gradually each year even within that window. Test old seed before relying on it for a full planting.
Do I need pesticides to grow Brussels sprouts?
No. Floating row covers or fine insect netting physically exclude most common brassica pests without needing to identify which one you're dealing with, and companion planting, crop rotation and hand-picking cover the rest for a home-scale planting.