If you want an early harvest without babysitting every seedling, this is your window. From now through April 20, cool soil is your ally. These cold-hardy crops handle late frosts, jump out of the ground in low temps, and usually face fewer spring pests. Translation: less time fussing, more time snacking on your own greens.
Radish, turnip, and summer radish
Get radish into the ground early, while the weather stays on the cool side. At 5–6°C, expect sprouts in about a week; warm the soil to 12–15°C and they pop in 3–4 days. Early timing also helps you sidestep crucifer flea beetles. Turnip and summer radish go in during the same early stretch.
Peas
Pea seedlings shrug off dips to -5°C. With soil around 10°C, seeds germinate in 7–10 days. Planting on the early side delivers a uniform flush of pods, and the peas come out clean and worm-free.
Leaf lettuce
Lettuce tolerates brief freezes down to -5°C. Sown early, the leaves stay juicy and mild for longer, and the plants hold off on bolting.
Dill
As soon as the snow melts and the ground thaws, in it goes. Dill germinates at just 5–6°C.
Spinach
Wait until the soil warms to about 10°C before you sow. That timing keeps bolting risk in check and sets you up for lush leaves instead of surprise flower stalks.
Arugula
Arugula is a short-day plant, which is a fancy way of saying May–June heat pushes it to flower fast. Seed it as early as possible so the leaves stay tender longer.
Parsley (leaf and root)
Sow in early spring once temperatures hold above freezing and the soil has thawed. Leaf parsley lets you cut 2–3 times in one season. Root parsley gets a full run at sizing up before cold weather returns.
Bunching onion (Welsh onion)
Earlier is better. Spring moisture boosts germination, and with an early start you can get 1–2 harvest cuts in the first year by the end of July.
Carrots
Get carrots in right after snowmelt. They love that spring moisture and emerge faster with it. Aim for soil at 8–10°C. This is the sweet spot for sowing early, medium-early, and midseason varieties.
Bottom line: use the cool spell through April 20 to load the beds with these stalwarts. The season will feel longer, the greens will taste better, and you will look very smart when everyone else is still waiting for 'garden weather.'