Cut Flower Garden Planner

The tool splits your total bed area evenly across however many species you select, then divides each share by that species' typical spacing (for example a Zinnia needs about 23cm x 23cm, so roughly 0.053 m² per plant). A 4.5 m² bed split four ways gives 1.125 m² per species — enough for 21 Zinnias, or 28 Sweet Peas at a tighter 20cm spacing, or just 5 Dahlias at a wider 45cm spacing.

Because each Sunflower plant and each Gladiolus corm produces essentially one useful cutting flush — a Gladiolus corm gives one flower spike that lasts about two weeks, according to Longfield Gardens' succession-planting guide. To keep cutting continuously, growers plant three separate batches roughly 2-3 weeks apart; this tool models a fixed 3-week gap between rounds and multiplies the plants-per-round figure by 3 for these two species.

It compares your earliest first bloom against the date the last of your selected species opens — for a succession-planted species (Sunflowers, Gladioli) that means the last of its 3 rounds, sown 3 weeks apart, not just the first round. A gap of 4 weeks or more scores "Good Season Spread." A gap of 2 to 3 weeks scores "Some Clustering" — Cosmos (8 weeks after frost) with Snapdragons (10 weeks) is the common case. You will cut flowers across that fortnight, but they open close enough together that the season peaks and fades in one go rather than running on; a species at least 4 weeks off your earliest is the fix. A gap under 2 weeks — for example choosing only Sweet Peas (12 weeks after frost) and Dahlias (13 weeks), neither succession-planted — scores "Blooms Cluster Together," meaning you'll get one concentrated cutting window rather than flowers spread through the season.

From four broad UK bands based on multiple UK gardening sources (GardenFocused and Glorious Garden): South England & South Wales around 8 April, Midlands & Northern England around 20 April, Scotland Lowlands & Northern Ireland around 1 May, and Scotland Highlands & exposed/upland areas around 20 May. These are regional generalisations, not a postcode-specific forecast.

Because the tool measures weeks from last frost to first bloom, not sowing order. Cosmos is a half-hardy annual normally started indoors and planted out around the last frost date, then flowers roughly 8 weeks later. Sweet Peas are often sown much earlier (autumn or late winter) but their longer 12-20 week growth cycle still puts first bloom around 12 weeks after the last-frost reference point, per the National Sweet Pea Society's growing guide.

A plant that keeps producing new stems for weeks after you start cutting, rather than flowering once and finishing. Sweet Peas, Cosmos, Zinnias, Snapdragons and Dahlias are all treated as cut-and-come-again in this tool — regular cutting encourages more blooms from the same plants, so one sowing supports an extended cutting season without needing extra seed.

Yes, and many growers do — a second sowing of Zinnias or Cosmos three to four weeks after the first extends the season and gives fresher stems later on. This tool only applies fixed succession rounds to Sunflowers and Gladioli because those two genuinely need it to produce any continuous supply; for the other five, treat the tool's totals as a minimum and add an extra sowing manually.

Yes — measure or estimate the total area in square metres and enter a length and width that multiply to roughly that figure (for example a 6 m² L-shaped bed could be entered as 3m x 2m). The spacing maths only uses the total area, not the actual shape, so the plant counts will still be accurate; you'll just need to lay the plants out to fit your bed's real outline yourself.

Each species gets a smaller area share, and the wider-spaced species (Dahlias and Sunflowers at 45cm) can round down to 0 plants if their share is too small to fit even one at that spacing — the breakdown table will show 0 for that row rather than an error, so you can see exactly which species don't fit.

It means every species you selected rounds down to 0 plants for your bed size — usually because too many species are splitting too small a bed. The Assessment names the exact area each species is getting so you can see the problem, and the fix is either to select fewer species or enter a larger bed length/width.

No — it's a single flat percentage meant to cover germination failure, transplant losses, slug and pest damage and other losses together, not broken out by cause. The default 15% is a reasonable starting buffer for a typical UK garden; increase it if you have a known slug problem or are direct-sowing outdoors where losses tend to be higher.

Seed and corm pack sizes vary hugely by supplier and species (a Zinnia seed packet might hold 30-50 seeds; a Dahlia tuber or Gladiolus corm is usually sold individually), so the tool gives you the raw quantity needed and leaves the pack-size maths to you when ordering — dividing the "seeds/corms to buy" figure by your supplier's pack size tells you how many packets to order.

No — it's a quantity and timing planner, not a layout designer. It tells you how many of each flower fit your bed area and roughly when they'll start blooming, but it doesn't lay out rows, paths, support structures (Sweet Peas and Dahlias both typically need staking or netting) or companion planting. Use it to plan quantities and a shopping list, then design the physical layout yourself.

Treat them as planning estimates, not guarantees. Every figure in the Reference Figures table is a representative point drawn from a published range — actual bloom timing depends on the specific variety you buy, the weather that season, and your site's own conditions, and can reasonably vary by two weeks or more in either direction.