How SproutRow Works
This page explains the Plot Planner fit score, the frost dates behind every planting window, how to find your zone, how regions outside the US work, where the crop data comes from and how pet safety is decided. Nothing here is secret, and nothing is paid placement.
The fit score, step by step
The planner first hides crops that cannot work for you. Then it scores the rest from 0 to 100.
Crops that get hidden
- Space. If you grow on a balcony, in pots or on a windowsill, crops marked “beds only” are hidden. On a windowsill, crops that need a pot bigger than 2 gallons are hidden too.
- Sun. Each crop has a minimum number of direct sun hours. “Under 3 hours” counts as 3, “3 to 5 hours” counts as 5 and “6 hours or more” counts as 8. A crop that needs more than your number is hidden.
- Pets. If you tick “pets at home”, crops listed as toxic to cats or dogs are hidden. Crops marked “check” stay in the list with a small flag.
How the points add up
- Ease, up to 25 points. Each crop has a difficulty from 1 (very easy) to 5 (demanding). A first season gardener is matched to difficulty 2 or lower, “some seasons” to 3 or lower, and an experienced gardener to anything. Every point of difficulty above your level costs 10 points.
- Time, up to 15 points. A crop’s weekly need is its difficulty plus its water need, divided by two. Under 1 hour a week covers a need of 2, 1 to 3 hours covers 3.5 and 3 hours or more covers 5. Every point of need above your time costs 6 points.
- Use, up to 25 points. If you pick nothing under “what you want to eat”, every crop gets 15. If you pick something, a crop with no match gets 4, one match gets 20 and two or more matches get 25.
- Planting window, up to 25 points. “Plant now” gets 25 and “start seeds indoors now” gets 22. “Wait until” gets 24 minus 2 for every week you would wait, with a floor of 6. “Too late this year” gets 2.
- Space fit, up to 10 points. In beds and yards every crop gets 10. In pots, crops marked “great in pots” get 10 and “fine in pots” get 5.
The five parts are added and rounded. A score near 100 means an easy crop you want to eat, in a window that is open, in a spot it likes. A low score is not a “no”. It usually means “later” or “more work than you planned”.
How the planting status works
Every crop stores its planting weeks relative to frost, not calendar months. A tomato, for example, goes outside from about the last spring frost to a few weeks after it. The planner turns those weeks into dates for your zone, then compares them with today (or the month you pick under “pretend it is”).
- Plant now: today falls inside the outdoor window, in spring or in fall.
- Start seeds indoors now: today falls inside the window for sowing seeds inside.
- Wait until: the next window opens within about four months. The date shown is when it opens.
- Too late this year (try fall): nothing opens for this crop in the next four months. Look at crops with a fall window instead.
Frost dates used by the planner
These are typical average dates. Half of all years have a frost later than the average spring date, so many gardeners wait an extra week or two for tender crops.
| USDA zone | Average last spring frost | Average first fall frost |
|---|---|---|
| 3 | May 15 | September 15 |
| 4 | May 10 | September 25 |
| 5 | April 30 | October 10 |
| 6 | April 20 | October 20 |
| 7 | April 10 | October 30 |
| 8 | March 25 | November 10 |
| 9 | February 25 | December 1 |
| 10 | January 31 | December 20 |
| 11 | No frost | No frost |
Zone 11 has no regular frost. For it the planner borrows the zone 10 dates, and in practice heat matters more than cold there.
Gardening outside the United States
Every planting window is set by two dates: the average last frost in spring and the average first frost in autumn. USDA zones are only one way to get those dates. In the region list you can also pick Canada, the United Kingdom and Ireland, much of Europe, Australia or New Zealand, or type in your own two dates under “I know my frost dates”. The planner, the calendar, My plot and every crop timeline then use those dates. The tools try to guess your region from your device’s time zone and language the first time you visit, and say which one they picked. Nothing is sent to us to make that guess. Your own choice always wins and is remembered in this browser.
What counts as a frost: in Canada, the date is the Environment Canada 30-year average of the last spring day and the first autumn day with a minimum of 0 C or lower. In the UK, Ireland and Europe we worked the dates out ourselves from daily station records of the national weather services for 1991 to 2020, as the average last spring day and first autumn day with an air minimum below 0 C. In Australia and New Zealand we follow the Bureau of Meteorology rule that a screen temperature of 2 C or lower means frost is likely at ground level, because air frosts are rare in the big cities but ground frosts are not. Each date is rounded to the nearest 5 days, and where stations in one region disagreed we used a typical date in between. Every date is an average for a typical garden in the region. Your own frost dates can be 2 to 3 weeks either side, so check a local source if you can.
The southern hemisphere: in Australia and New Zealand the seasons are reversed, so the spring frost is the last one in August to October and the autumn frost the first one in April to June. The crops keep the same rules, for example “plant out from one to four weeks after the last spring frost”, and the tools turn them into real calendar dates. The calendar strip, the “pretend it is” month and every “Wait until” date use the normal calendar, so a tomato in Melbourne shows up in September and October, not in April. Spring windows count from the last spring frost and autumn windows from the first autumn frost, even when that autumn frost falls in the next calendar year.
Frost-free regions (Sydney, Brisbane, Auckland, the Spanish and Portuguese coast, southern Italy and the Greek coast): if fewer than half of the years have a frost, we treat the region as frost-free and use a simple rule instead of frost dates. Cool-season crops such as lettuce, peas and broccoli go in during the cool months, from October to February in the north and from April to August in the south. Warm-season crops such as tomatoes and beans can go in at any time except the two hottest and the two coolest months: March to June and September to October in the north, September to December and March to April in the south. Hot summers and short winter days slow everything down, so these windows are a starting point, not a promise.
Seed packets often give USDA zones, so every region also shows a rough USDA zone. Treat it as a hint for matching packets, not as an exact zone.
Region frost dates and their sources
| Region | Average last spring frost | Average first autumn frost | Rough USDA zone | Source |
|---|---|---|---|---|
| Vancouver and coastal BC | March 20 | November 10 | 8b | Environment Canada, Canadian Climate Normals 1981-2010 (MSC GeoMet climate-normals API), "Mean date last frost in spring" and "Mean date first frost in fall"; Vancouver Intl A (1108447): Mar 18 and Nov 10. |
| Calgary and the prairies | May 20 | September 15 | 4a | Environment Canada, Canadian Climate Normals 1981-2010 (MSC GeoMet climate-normals API), "Mean date last frost in spring" and "Mean date first frost in fall"; Calgary Intl A (3031093): May 21 and Sep 16. |
| Toronto and southern Ontario | April 30 | October 15 | 6a | Environment Canada, Canadian Climate Normals 1981-2010 (MSC GeoMet climate-normals API), "Mean date last frost in spring" and "Mean date first frost in fall"; Toronto Pearson Intl A (6158733): Apr 30 and Oct 16. |
| Montreal and southern Quebec | April 30 | October 10 | 5a | Environment Canada, Canadian Climate Normals 1981-2010 (MSC GeoMet climate-normals API), "Mean date last frost in spring" and "Mean date first frost in fall"; Montreal Trudeau Intl A (7025250): Apr 29 and Oct 12. |
| Halifax and Atlantic Canada | May 5 | October 20 | 6a | Environment Canada, Canadian Climate Normals 1981-2010 (MSC GeoMet climate-normals API), "Mean date last frost in spring" and "Mean date first frost in fall"; Halifax Stanfield Intl A (8202250): May 7 and Oct 18. |
| South England | April 15 | November 5 | 8b | Met Office station records via NOAA NCEI GHCN-Daily: Hurn Apr 25 and Oct 24, Wisley Apr 26 and Oct 27, Oxford Apr 2 and Nov 11; Meteostat daily data (from national SYNOP reports): Odiham Apr 11 and Nov 11, Boscombe Down Apr 17 and Nov 8. |
| London and the Thames Valley | March 30 | November 15 | 9a | Met Office station records via NOAA NCEI GHCN-Daily: Heathrow Mar 26 and Nov 15; Meteostat daily data (from national SYNOP reports): Heathrow 03772 Apr 1 and Nov 11. |
| Midlands and north England | April 15 | November 5 | 8b | Met Office station records via NOAA NCEI GHCN-Daily: Nottingham Watnall Apr 5 and Nov 11, Sheffield Apr 3 and Nov 18, Durham May 1 and Oct 30; Meteostat daily data (from national SYNOP reports): Birmingham Apr 18 and Nov 2, Manchester Apr 15 and Nov 4. |
| South-west England and coastal Wales | March 5 | December 5 | 9a | Met Office station records via NOAA NCEI GHCN-Daily: Valley (Anglesey) Mar 15 and Dec 2, Plymouth Mountbatten Mar 11 and Nov 30, Camborne Feb 16 and Dec 11. |
| Scotland (central belt and east) | April 25 | October 25 | 8a | Met Office station records via NOAA NCEI GHCN-Daily: Edinburgh Royal Botanic Garden Apr 17 and Nov 3, Aberdeen Dyce May 1 and Oct 26; Meteostat daily data (from national SYNOP reports): Glasgow Apr 30 and Oct 19, Edinburgh Turnhouse Apr 28 and Oct 23. |
| Northern Ireland | April 20 | November 1 | 8b | Met Office station records via NOAA NCEI GHCN-Daily: Armagh Apr 12 and Nov 9; Meteostat daily data (from national SYNOP reports): Belfast Aldergrove May 1 and Oct 23. |
| Ireland (east, Dublin) | April 20 | November 5 | 9a | Met Eireann station records via NOAA NCEI GHCN-Daily: Dublin Phoenix Park Apr 21 and Nov 7; Meteostat daily data (from national SYNOP reports): Casement Apr 24 and Nov 1. |
| Ireland (west and south-west coast) | March 15 | November 25 | 9b | Met Eireann station records via NOAA NCEI GHCN-Daily: Valentia Observatory Mar 5 and Dec 6; Meteostat daily data (from national SYNOP reports): Shannon Mar 20 and Nov 15. |
| Poland (north and Baltic coast) | April 25 | October 20 | 7a | IMGW-PIB public daily synop data (danepubliczne.imgw.pl): Elblag-Milejewo Apr 25 and Oct 24, Szczecin Apr 22 and Oct 18. |
| Poland (centre) | April 25 | October 15 | 6b | IMGW-PIB public daily synop data (danepubliczne.imgw.pl): Warszawa-Okecie Apr 22 and Oct 19, Poznan-Lawica Apr 24 and Oct 17, Lodz-Lublinek Apr 25 and Oct 17. |
| Poland (south) | April 25 | October 15 | 6b | IMGW-PIB public daily synop data (danepubliczne.imgw.pl): Krakow-Balice Apr 22 and Oct 17, Wroclaw-Strachowice Apr 22 and Oct 18, Katowice-Muchowiec Apr 27 and Oct 15. |
| Germany (north and Berlin) | April 20 | October 30 | 8a | DWD station records via NOAA NCEI GHCN-Daily: Hamburg-Fuhlsbuettel Apr 24 and Oct 29, Bremen Apr 25 and Oct 29, Hannover Apr 22 and Oct 29, Berlin-Tempelhof Apr 5 and Nov 4. |
| Germany (south) | April 15 | October 30 | 7b | DWD station records via NOAA NCEI GHCN-Daily: Muenchen-Nymphenburg Apr 7 and Nov 4, Stuttgart-Echterdingen Apr 14 and Oct 25, Augsburg Apr 27 and Oct 19, Freiburg Apr 4 and Nov 8. |
| Netherlands and Belgium | April 15 | November 5 | 8a | KNMI and RMI station records via NOAA NCEI GHCN-Daily: De Bilt Apr 17 and Nov 3, Uccle Apr 5 and Nov 13, Eindhoven Apr 24 and Oct 29. |
| France (north and Paris) | April 5 | November 10 | 8b | Meteo-France station records via NOAA NCEI GHCN-Daily: Paris-Orly Mar 31 and Nov 12, Lille-Lesquin Apr 2 and Nov 14, Rouen-Boos Apr 6 and Nov 15, Strasbourg-Entzheim Apr 8 and Nov 1. |
| France (south) | February 25 | November 30 | 9a | Meteo-France station records via NOAA NCEI GHCN-Daily: Toulouse-Blagnac Mar 6 and Nov 23, Marseille-Marignane Feb 20 and Dec 5, Montpellier Feb 20 and Dec 1, Bordeaux-Merignac Mar 6 and Nov 26. |
| Spain (north and central) | April 1 | November 10 | 8b | AEMET station records via NOAA NCEI GHCN-Daily: Madrid-Barajas Mar 25 and Nov 19, Burgos-Villafria Apr 26 and Oct 24, Valladolid-Villanubla Apr 26 and Nov 4, Zaragoza Feb 23 and Dec 2. |
| Spain (south coast) | Frost-free most years | Frost-free most years | 10b | AEMET station records via NOAA NCEI GHCN-Daily: Malaga airport had a frost in 3 of 30 years and Almeria airport in none (1991-2020). |
| Portugal (Lisbon and the coast) | Frost-free most years | Frost-free most years | 10a | IPMA station records via NOAA NCEI GHCN-Daily: Lisboa Geofisica had no frost day in 1991-2020; Porto had one in 55 percent of years. |
| Italy (north) | March 10 | November 20 | 8b | Aeronautica Militare station records via NOAA NCEI GHCN-Daily: Verona Villafranca Mar 18 and Nov 15; Meteostat daily data (from national SYNOP reports): Milano Linate Mar 2 and Nov 27. |
| Italy (central) | February 25 | December 10 | 9a | Aeronautica Militare station records via NOAA NCEI GHCN-Daily: Roma Ciampino Feb 20 and Dec 15; Meteostat daily data (from national SYNOP reports): Pisa Mar 1 and Dec 5. |
| Italy (south and islands) | Frost-free most years | Frost-free most years | 10a | Aeronautica Militare station records via NOAA NCEI GHCN-Daily: Brindisi had a frost in 21 percent of years (1991-2020); Meteostat daily data (from national SYNOP reports): Napoli Capodichino in about half of the years. |
| Switzerland and Austria (lowlands) | April 5 | November 5 | 7b | MeteoSwiss and GeoSphere Austria station records via NOAA NCEI GHCN-Daily: Basel-Binningen Apr 5 and Nov 9, Geneve-Cointrin Apr 6 and Nov 6, Wien Mar 27 and Nov 7, Graz Apr 6 and Nov 4, Salzburg Apr 14 and Oct 23. |
| Czechia and Hungary | April 10 | October 30 | 7a | Meteostat daily data (from national SYNOP reports): Praha-Ruzyne Apr 21 and Oct 22, Budapest Pestszentlorinc Mar 29 and Nov 4; HungaroMet station records via NOAA NCEI GHCN-Daily: Szeged Apr 7 and Oct 25. |
| Sweden, Norway and Finland (south) | April 30 | October 15 | 6a | SMHI, MET Norway and FMI station records via NOAA NCEI GHCN-Daily: Stockholm-Bromma May 6 and Oct 8, Goteborg Apr 19 and Oct 26, Oslo Blindern Apr 25 and Oct 19, Helsinki-Vantaa May 9 and Sep 30. |
| Baltic states | May 1 | October 10 | 6a | Estonian and Lithuanian met service records via NOAA NCEI GHCN-Daily: Tallinn May 9 and Oct 10, Vilnius Apr 30 and Oct 5, Kaunas Apr 29 and Oct 9. |
| Greece and the Mediterranean coast | Frost-free most years | Frost-free most years | 10a | HNMS station records via NOAA NCEI GHCN-Daily: Athens Hellinikon had a frost in half of the years (1991-2020), and an autumn frost in 11 percent. |
| Sydney | Frost-free most years | Frost-free most years | 11a | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Sydney Observatory Hill had no day at or below 2 C in 1991-2020; Parramatta North had autumn frost days in 27 percent of years. |
| Melbourne | September 15 | May 30 | 10a | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Melbourne Airport Sep 7 and Jun 10, Laverton Oct 1 and May 26, Moorabbin Aug 29 and May 29, Viewbank Sep 15 and May 25, Scoresby Sep 22 and May 26, Bundoora Sep 15 and May 19. |
| Adelaide | August 1 | June 15 | 10a | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Adelaide Airport Aug 2 and Jun 14 (frost days in 70 percent of springs and 43 percent of autumns). |
| Perth | August 20 | June 10 | 10b | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Perth Airport Aug 22 and Jun 8 (frost days in 73 percent of springs and 37 percent of autumns). |
| Brisbane | Frost-free most years | Frost-free most years | 11a | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Brisbane Aero and Archerfield had a day at or below 2 C in fewer than half of the years (1991-2020). |
| Canberra and the tablelands (cold) | October 30 | April 15 | 8b | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Canberra Airport Comparison (1991-2010) Nov 2 and Apr 18; Meteostat daily data (from national SYNOP reports): Canberra Airport 94926 Oct 25 and Apr 12. |
| Tasmania | October 1 | May 5 | 9a | Bureau of Meteorology station records via NOAA NCEI GHCN-Daily: Hobart Ellerslie Road Aug 31 and Jun 2, Hobart Airport Sep 18 and May 22, Launceston Airport Nov 17 and Mar 27. |
| Auckland | Frost-free most years | Frost-free most years | 10b | Meteostat daily data (from national SYNOP reports) for Auckland Airport 93119: a day at or below 2 C in 42 percent of springs and 23 percent of autumns (1991-2020). |
| Wellington and Kapiti | September 5 | May 15 | 9b | NIWA station record via NOAA NCEI GHCN-Daily: Paraparaumu Oct 15 and Apr 27; Meteostat daily data (from national SYNOP reports): Wellington Airport Jul 28 and Jun 6. |
| Christchurch and Canterbury | November 10 | April 10 | 9a | Meteostat daily data (from national SYNOP reports) for Christchurch Airport 93780: Nov 9 and Apr 10 (9 complete years in 1991-2020). |
Station records come from the national weather services through the NOAA NCEI GHCN-Daily archive, the IMGW-PIB public data service in Poland and Meteostat (which collects the services’ daily SYNOP reports). Some regions are not listed because we could not check their dates yet.
Units and names
The site is written with US units and US crop names. Use the Units switch (at the foot of every page, in the planner and on crop pages) to show centimetres, litres and degrees Celsius instead. It turns on by itself when your region is outside the US, and it remembers your choice. Crop pages also list other common names, so courgette, aubergine, coriander, rocket, spring onions, beetroot and sweetcorn all lead to the right crop in the search box and the crop list.
How to find your zone
Your USDA plant hardiness zone is set by the coldest winter temperatures where you live. There are three easy ways to find it:
- Search for the USDA Plant Hardiness Zone Map from the U.S. Department of Agriculture and type in your ZIP code.
- Look at the back of a perennial plant tag from a local garden center. Many list the zones the plant suits, and staff usually know the local zone by heart.
- Call or email your county extension office. They can also give you local frost dates, which are more precise than any zone average.
A zone is a rough guide to frost dates, not an exact one. A valley, a city center or a south-facing wall can shift your own dates by a couple of weeks. If you know your local frost dates, choose “I know my frost dates” and type them in. Outside the US, pick your region from the list instead (see gardening outside the United States).
Where the crop data comes from
Spacing, days to harvest, sun needs, container sizes, companions, pests and planting weeks are checked against at least two sources for each crop. We favor university extension pages and use the Old Farmer’s Almanac, the Missouri Botanical Garden, the RHS and seed company growing guides for the rest. Each crop page lists its sources at the bottom. Where sources disagree we show a range, such as 60 to 85 days.
Companion planting advice deserves a note. Some pairings have research behind them, but much of it is long gardening tradition. We only list pairs that our sources agree on, and spacing, sun and water always matter more.
How pet safety is decided
Each crop carries one of three labels, based on the ASPCA toxic and non-toxic plant lists and veterinary sources:
- Safe: commonly listed as non-toxic to cats and dogs.
- Toxic: listed as toxic to cats, dogs or both.
- Check: some parts are fine and some are not, for example ripe fruit versus leaves and stems. The crop page says which parts.
Labels are general information, not veterinary advice. Any plant can upset a pet’s stomach. If a pet eats a plant and seems unwell, ask your vet or call the ASPCA Animal Poison Control Center at (888) 426-4435.
Mistakes
If a number or a date looks wrong for your area, write to contact@sproutrow.com. Please mention your zone, region or state so we can check against local sources.