March is the month the vegetable garden wakes up
Short answer
In March, sow broad beans, peas, parsnips, spinach and radishes outside, and carrots and lettuce from mid-month under cloches. Plant onion sets, shallots and first early potatoes late in the month. Indoors, sow tomatoes, peppers, leeks, brassicas, lettuce and herbs.
March is the month the vegetable garden wakes up. Outside, hardy crops go in: broad beans, peas, parsnips, spinach, radishes, onion sets and shallots, plus carrots and lettuce under cloches. Inside, it’s the main month for tomatoes, peppers, leeks and the first brassicas.
The deciding factor outside is the soil, not the date. If it sticks to your boots, wait. A week under a cloche or a sheet of plastic dries and warms it.
These timings are for a typical lowland garden in England or Wales, with a last frost around 20 April. In Scotland and the north, do the outdoor sowing in late March or early April.
Sow and plant outside
| Crop | When | Notes |
|---|---|---|
| Broad beans | All month | 5 cm deep, 20 cm apart |
| Peas | All month | Early varieties, 4 cm deep, with support |
| Parsnips | From mid-March | Fresh seed, 1 cm deep, slow to come up |
| Spinach | All month | Sow thinly |
| Radishes | All month | A short row every two weeks |
| Spring onions | All month | A pinch every three weeks |
| Carrots | From mid-month, under cloches | Early varieties such as Amsterdam Forcing |
| Lettuce | Under cloches | Or plant out module-raised seedlings |
| Onion sets and shallots | All month | Tips just showing, netted |
| First early potatoes | Late March | 30 cm apart, 12 cm deep |
| Asparagus and rhubarb crowns | All month | While dormant |
Sow indoors
- Tomatoes for an unheated greenhouse or outdoors.
- Sweet peppers, chillies and aubergines early in the month, if not sown in February.
- Leeks in a tray or modules for planting out in June.
- Cabbage, cauliflower, kale, Brussels sprouts and broccoli in modules.
- Lettuce, salad leaves and rocket for planting out in April.
- Beetroot and chard in modules, a few seeds per cell.
- Celery and celeriac with warmth, surface-sown.
- Herbs: parsley, chives, thyme and oregano.
- Flowers: sweet peas, calendula, cosmos and French marigolds.
Wait until April for courgettes, squash, cucumbers and beans. They grow fast and get pot-bound if sown now.
Jobs for March
- Warm the soil with cloches, fleece or sheeting.
- Prepare seedbeds. Rake to a fine tilth once the soil has dried.
- Weed. Weeds start fast in March. Hoe on dry days.
- Feed and mulch fruit bushes and rhubarb.
- Watch for slugs around new sowings.
- Harden off broad beans and peas raised in pots before planting.
What to harvest
Leeks, kale, purple sprouting broccoli, spring cabbage, the last parsnips, forced rhubarb and overwintered salads.
For next month, see what to sow in April, and planting potatoes for earlies in detail.
Questions people also ask
Is it too cold to sow outside in March?
For hardy crops, no, as long as the soil isn't frozen or waterlogged. Broad beans, peas, parsnips, spinach and radishes all germinate in cool soil. Cover beds with cloches or fleece for a week beforehand to warm them.
When should I plant first early potatoes?
From late March in the south and mid-April further north. The shoots take a few weeks to come up, and you can earth them over if frost threatens.
Can I sow tomatoes in March?
Yes, March is the best month for tomatoes that will go into an unheated greenhouse in late April or outside in late May.
Dates set to your own frost dates
VegLog works out sowing and planting times for your town, then reminds you when each job is due.
