Three vegetables for March — and why peppers have to wait

In March, in a Swiss climate, you can't sow everything outside. But you can sow more than most people think.

The problem: most people wait until late April, because they've heard somewhere "after the ice saints" and they think that's the one gardening rule to know. The ice saints (11-15 May, traditional late-frost warning days) only apply to frost-sensitive plants, though. And here's the thing: there's a whole category of vegetables that isn't frost-sensitive. On the contrary, they grow best while the soil is still cool.

Three of them can go out in March right now.

1. Radishes

Radishes are the ideal starter. Three to four weeks from sowing to harvest — the fastest vegetable there is. Sow in early March and you'll have your first bowl by early April.

What you need: sow in rows, 2 cm deep, 2 cm apart within a row, 15 cm between rows. They germinate at 5 °C, they're happy up to 18 °C. Once summer hits and the temperature climbs above 20 °C, they turn woody and sharp — that's the end of radish season.

My tip: don't sow all at once. Sow a new short row every 10 days. That way you'll have fresh radishes from March to May instead of eighty at once.

2. Spinach

Spinach loves the cold. It actually needs it: above 20 °C it immediately bolts and turns bitter and tough. That means spinach is strictly a spring and autumn vegetable in Switzerland.

March and early April are perfect. Spinach germinates at 4 °C, which makes it one of the most robust vegetables for a garden bed.

What you need: sow 2-3 cm deep, 5 cm apart, 25 cm between rows. Harvest after 6-8 weeks — either pull whole plants or just pluck the outer leaves, which will re-grow.

Variety tip: "Matador" is old, proven and frost-hardy down to -5 °C. "Giant Winter" goes as low as -8 °C, if you want to sow again in September for an autumn harvest.

3. Pak choi

Here's the insider tip: pak choi. Still under-represented in European gardens, even though it fits our climate perfectly.

Pak choi is an Asian cabbage with tender leaves and crunchy stems. It grows fast (40-50 days), tolerates light frost, and tastes mildly nutty and fresh. Pan-fried or raw in a salad — either works.

What you need: sow in rows, 1 cm deep, 10-15 cm apart, 25 cm between rows. Important: pak choi likes consistent moisture, so don't let it dry out. Drought stress makes it bolt (flower), and then it's inedible.

My tip: baby pak choi comes as special varieties ("Joi Choi" for example) that you can harvest after just 3 weeks.

And why pepper can't go out in March

Peppers come from Central America. Their seeds germinate reliably at 22-28 °C. At 18 °C some of them still sprout. Below 15 °C: forget it.

Now guess how warm your bed soil is in March. In most of Switzerland the soil temperature in March sits between 5 and 10 °C. Peppers would simply rot in that earth without ever germinating.

Peppers belong indoors, on the windowsill, from late February to early March. And only mid-May (after the ice saints) do they go out into the bed, once soil and air are warm enough.

Same applies to tomatoes, eggplants, zucchini, cucumbers, and basil. All "warmth children". They have no business being outside in March.

The takeaway

In March the rule is: leafy greens and root vegetables are your friends. Fruit vegetables have to wait.

Once you've internalised that, you can fill the March-April window of your bed with vegetables that will have been harvested by the time the ice saints come around. After that, tomatoes and zucchini move into the same spaces — that's called pre-cropping, and it doubles your yield on the same area.

Erntezeit plans this automatically: if you select radish and tomato, we'll suggest putting the radishes into the same bed segment where the tomatoes will later go. No space wasted, no head-scratching.

🦔 Stachi