Mid-March is a turning point in the gardener’s calendar. If you’re planning to grow tomato and pepper seedlings, this is the last call to sow the seeds. In two or three weeks it may already be too late—plants might not reach the fruiting stage before the end of summer. But remember: simply putting seeds into soil is only the beginning. The real challenge starts when the first delicate seedlings appear on the windowsill.

Let me remind you of a few key things: how not to drown your seedlings, what to do when there isn’t much sunlight on the windowsill, what you can already sow directly into the ground, and why it’s worth checking your garden beds for the first tiny carrot leaves.

If you want to enjoy your own tomatoes and peppers this season, the second half of March is the absolute deadline. Both tomatoes and peppers need a long growing season. When sown in mid-March, they’ll be ready to transplant outdoors around the turn of May and June. If you wait until April, the plants will be weaker, and the fruit may not ripen before the first autumn frosts.

Peppers take longer to sprout than tomatoes and need a higher temperature to germinate (optimally around 25°C or 77°F). It’s a good idea to place the containers on a warm windowsill above a radiator or use a heating mat.

The biggest damage to young seedlings usually isn’t caused by pests—but by gardeners themselves. Kind hearts and too much watering.

Here are the three main sins:

• Seedlings have delicate, shallow roots. If the soil stays constantly wet, the roots literally drown—there isn’t enough oxygen, and they begin to rot. A common symptom is seedlings collapsing right at the base. This is called damping-off, a fungal disease that develops in overly moist conditions. How to avoid it? Water only when the top layer of soil has dried out.
• Seedlings don’t like wet foliage. Water droplets can act like tiny lenses and burn delicate tissues in sunlight. Moist leaves are also an open invitation for fungi. Always water into the tray or directly onto the soil, avoiding the green parts of the plant.
• Water straight from the tap is often very cold. For young roots, that’s a temperature shock. Always let water sit for a few hours so it can reach room temperature before watering.

Not everyone has a south-facing windowsill where the sun shines all day. If your windows face east, west, or especially north, seedlings may struggle. They will stretch toward the light, developing pale, thin stems that can’t support the leaves. In that case, consider installing red-blue LED grow lights.

Why red and blue specifically? Blue light stimulates the growth of leaves and stems, helping plants grow compact and strong. Red light is responsible for flowering and fruit development. The combination of these two wavelengths gives plants exactly what they need during the seedling stage. You don’t need a professional setup—small LED grow lights with suction cups or red-blue LED strips that can be mounted above the windowsill work perfectly well. Ideally, they should shine for 6–9 hours a day, preferably in the morning and evening to complement natural sunlight. But even 3 hours a day is better than none.

Seedlings aren’t everything. Mid-March is also the moment when the first seeds can go directly into the ground. Of course, that’s only if the soil isn’t frozen and has dried out at least a little.

What can you confidently sow right now?

• Broad beans – one of the earliest vegetables. They tolerate light frost and, when sown in March, will produce a harvest before the summer heat arrives.
• Peas – like broad beans, they enjoy cool weather. They germinate quickly and tolerate temperature fluctuations well.
• Spinach – the earlier the better. Spring spinach is the tastiest.
• Butterhead and leaf lettuce – you can sow them directly into the soil, but keep some frost cloth handy in case of stronger frosts.
• Radishes – a classic spring vegetable. Sow in March, harvest in May.
• Carrots – if you didn’t manage to sow them in February, March is still fine. They’ll be ready a little later but well before winter.
• Leaf parsley – it germinates slowly, but the earlier you sow it, the longer you’ll be able to harvest the leaves.

If your garden tends to be cool and wet, it’s worth considering sowing in polytunnels or simple plastic tunnels. The soil warms up faster there, and the seeds are less likely to rot.

If you sowed carrots and root parsley around the turn of February and March, the first tiny leaves should start appearing right about now, in mid-March. This is the moment when many gardeners start to panic a little. Did nothing germinate? Should I sow again? Relax. Carrots and parsley take a long time to sprout—sometimes even 3–4 weeks. If you don’t see green rows yet, give them time. But if a full month has passed and the bed is still empty, you can gently move the soil aside and check whether the seeds have started to sprout at all. Sometimes patience is enough. Other times, you may need to reseed in April.