GardenAnnual Plant · 5 varieties
Flax
Linum usitatissimum
Linaceae — the only crop in its plant family here.
Flax (Linum usitatissimum) is an annual plant. It wants full sun and pH 6–6.5 soil, with about 1 in of water weekly. It matures in about 90–120 days from sowing. Watch for cutworms and rust. Below: its full sourced profile from 5 extension sources, plus a planting calendar timed to your frost dates.
Typical dates for zone 6b — set your zone or ZIP for yours. This calendar assumes the crop is direct sown. Timing is a guide from the crop's sourced growth stages; confirm with your local frost dates and extension before you sow.
What we will not put a number on
We do not give a feeding rate for this crop, and that is deliberate rather than a gap. The figures published by extension services are pounds of nitrogen per acre for a production field — they do not convert safely to a raised bed or a pot without knowing your soil test and your fertilizer's analysis, and guessing errs toward burning roots. It is also why every chart you find online disagrees with the next one.
We give watering as a depth per week rather than gallons per plant, because that is how it is actually measured and how the published figures are written. A gallons-per-plant number depends on your spacing, your soil and whether the plant is in a pot — so it would look more precise than it is.
Site & soil
- Sun
- Full sun
- Soil pH
- 6–6.5
- Soil texture
- Well drained, Loam, Clay
- Frost tolerance
- Half hardy
No published figure for the temperature frost starts to hurt it, the temperature that would kill it and a heat limit. We looked — where a number is missing here it is missing from the research, not skipped. The crop’s frost and heat tolerance above still applies.
The plant
- Mature height
- 1–3 ft
- Mature spread
- 2–6 inest
- Growth rate
- Moderateest
- Spacing in row
- 1–2 inest
- Between rows
- 4–8 inest
- Planting depth
- 0.5–1.5 in
- Container size
- 2–5 gal — low end is the minimum, high end is betterest
- Support
- Self-supportingest
- Grown from
- Direct sow
Water & feeding
- Water needs
- Moderate
- Water per week
- 1 in/wkest
- Critical water
- Floweringest
- Feeding
- Low
Timing & fruiting
- Days to maturity
- 90–120 days from seed
- Harvest cues
- Lower leaf yellowingest
Planted again for autumn
- Sow by
- late Jul typical · zone 6b
90 days to maturity from sowing, counted back from the first frost above. Not published for anywhere in particular: it is your own frost date and this crop's own figure, which is why it works wherever you are. A days-to-maturity figure is a catalog number for a good season rather than a promise, and a cold month moves it.
Edible parts per source: seed.
Compiled from the extensions cited below. Which ones actually show up depends on your region — your extension's local list is the last word.
Different parts differ — the edible part is the seed; the notes below flag other parts or preparations.
PeopleToxic raw seeds, Toxic leaves, Contact dermatitis
Recorded exactly as the source states it — not medical or veterinary advice. If a person or animal may have eaten a toxic part, call Poison Control (1-800-222-1222) or your vet / the ASPCA line (888-426-4435).
| Variety | Type | Days | Color | What it is known for |
|---|---|---|---|---|
| Cascade Heirloom | Fiber | 90–120 | Oregon Agricultural Experiment Station / Oregon State College (Hurst, Nelson, Harmond, Klein & Fishler) records this asgives a heavy crop | |
| Common Heirloom | Oilseed | 100–120 | Brown | World Seed Supply describes this asgrown to look at |
| Evelin | Fiber | 90–120 | ||
| Linore Heirloom | Fiber | 100–110 | Truelove Seeds describes this astakes the cold · grown to look at | |
| Marilyn | Fiber | 90–120 | Brown | Great Lakes Staple Seeds describes this asgrown to look at |
- Alternative Field Crops Manual (Univ. of Wisconsin-Extension and Univ. of Minnesota; Purdue NewCROP host)
- NC State Extension Gardener Plant Toolbox
- NDSU Extension (A1038, Revised May 2020, revised by Hans Kandel and Clair Keene) — cited at the UW-Madison Extension-hosted copy of the PDF, because ndsu.edu returns HTTP 403
- University of Wisconsin-Madison Division of Extension (Crops and Soils)
- Utah State University Extension
We compile bare facts from these university-extension and horticultural sources, never copied prose. 10 of the 19 values on this page carry a citation. The rest are marked est; hover one and it says why — either nobody publishes a figure we could point at, or a person set it and attached no source. Figures vary with climate and seed source; confirm with your local extension before you buy.
Growing more than flax? Browse all crops, or grab the spacing calculator and frost date lookup. The GardenTrack app (now in beta) remembers what you planted and where, then tells you what to do and when. Join the beta →