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9 Vegetables to Start Indoors in April | Almanac.com

9 Vegetables to Start Indoors in April

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Start growing these vegetables in early spring!

With the arrival of spring, the growing season is now raring to go! But what can you sow in April? Even if it’s cool outside, you can start these 9 vegetable seeds indoors, in order to transplant into the garden as soon as the temperatures are warm!

See how to start sowing your favorite vegetables inside—from zucchini to winter squash. This assures you’ll get vegetables to ripen and harvest much faster!

Of course, there are also cool-season vegetables that you can sow outside in early spring! See the best vegetables for cool weather.

Let’s get started with some warm-season crops, beginning with a personal favorite…zucchini.

1. Sowing Zucchini

These hard-working vegetables are perhaps the most productive of all. Once they get going, they’ll keep pumping out the fruits – your main job is to keep picking them! 

Sow these big, easy-to-handle seeds into these chunky plug trays, which should give them enough space to grow till they are planted outside after the last frost. If not, well, it’s easy to move them onto a larger pot till it is.

Now, there’s some debate about whether the seeds should be sown on their side or not. The argument goes that by sowing the seeds on their side, water can’t collect on top of the seed and cause it to rot. Sow them at the right time so germination is speedy, and this really shouldn’t be an issue.

Dib a hole into the compost with your finger, then pop the seed in and cover it to a depth of about half an inch or 1 cm deep or so. Learn more about planting zucchini.

2. Sowing Winter Squash and Pumpkins

Squash and pumpkins are sown the same way. Here are two delicious varieties: an orange ‘onion’ squash and the absolute royalty when it comes to taste, a variety called ‘Crown Prince’. Use an all-purpose, peat-free potting mix.

Zucchini can be started later in spring, even early summer, and the plants will soon catch up. But in typically cooler summers, winter squash needs as long a growing period as you can offer them, so it pays not to delay sowing for these guys.

Give the zucchini and squash water and bring them indoors to germinate in the warm. They’ll come back out here the moment they poke through. Read our winter squash growing guide for more information.

3. Sowing Beans

Every garden needs beautiful climbing or pole beans. Both runner beans and French beans (haricot beans) are wonderful varieties. A tip: Grow two types of beans because if one of them suffers due to unseasonal heat – or chill – there’s the other to fall back on. French beans are often more susceptible to the cold, while runners can struggle in the heat.

Beans can be sown later in spring – either directly where they are to grow or into pots or chance things with slightly earlier sowing. Use plug trays or sow into small pots. Again, use an all-purpose potting mix and pop the seeds in at a depth of around an inch or 2 cm, although a simple rule of thumb is simply to cover any seeds with a depth of potting mix equal to the size of the seed.

The young plants will go out after the last frost date once they’ve been properly hardened off, which is when you acclimate plants to outdoor conditions over a period of about a week so that they get used to being outside. If you can’t guarantee a frost-free environment, wait until late spring to sow your climbing beans, when the generally warmer conditions will soon see plants catch up with those started off earlier.

Learn more about planting beans!

4. Sowing Corn

There’s nothing like a freshly picked cob of sweet corn to get you salivating. Absolute bliss! Corn is also planted after the risk of frost has passed, and once warmer weather sets in, it’s genuinely astonishing how quickly they’ll grow! 

If you’re growing anywhere with shorter summers, sow a variety specifically bred for cooler conditions. You can sow them directly in late spring or start earlier by sowing indoors in bigger plug trays. Dib a hole, drop one seed in per plug… and cover them back over. 

Watch out for mice! One trick to mouse-proof your sowings is to pop them into a lidded container till they pop through. Or, you could use a propagator and lid if you have one, which would also help to retain moisture and warmth.

Consider growing corn in your garden this year with these tips.

5. Sowing Carrots

Starting off in plug trays or pots is great for getting a head start earlier in the growing season or to overlap crops, so one can be started off while the other is still in the ground, finishing off. For example, plant summer-sown kale once the last of the carrots is lifted. But some veggies are best sown directly where they are to grow, especially those that produce a long edible taproot that could get damaged if plants are transplanted.

Carrots are one of those, and sowing them is intensely satisfying. Mark out a shallow drill a little less than half an inch or 1 cm deep… and now for the seeds. They’re tiny, so it’s worth taking a little care and time to space them out. The aim is for a couple of seeds every half inch or centimeter of the row. And then just cover them back over. Perhaps add a couple of sticks at the end of both rows so that you know where the seedlings will pop up. The seedlings will be thinned to leave a couple every inch or so, or one per centimeter.

We make growing carrots easy! Learn more here.

6. Sowing Parsnips

Parsnips can be slow to germinate in cold soil, so there’s little point rushing things. If it’s still on the cool side, just wait another week or two. How do you know if the soil’s too cold? Well, the traditional advice is to sit on it on your bare bottom, and if it’s comfortable to do so, you’re good to go. But the back of the hand is also fine!

Mark out a few drills about a foot or 30 cm apart. These seeds are easy to handle one a time. Sow a couple per inch, or one every centimeter or so. Parsnips can take up to four weeks to appear! So a little tip is to sow some radishes in the same row. These will come up within a matter of days, helping to mark out the position of the row so you can safely weed around them. And let’s cover them over and give the area a good watering.

Once the radishes are harvested, the parsnip seedlings will have more room to really pull away, and then these, in turn, can be thinned to about 6 inches or 15 cm apart. Yes, parsnips are slow to germinate, but honestly, aside from that, they are a really resilient, low-fuss root crop.

7. Sowing Broccoli

When you harvest broccoli, you get a secondary cut of smaller heads by simply leaving the plants to grow on. This means a cropping period of up to a month for this nutrient-dense green.

Sow the seeds into pots, just covering them with potting mix. They germinate pretty quickly, and then you can carefully transfer one seedling into each plug to grow on till it’s their turn to plant out – under insect mesh or fine netting to keep egg-laying butterflies off.

Check out our broccoli growing guide for more information.

8. Sowing Celery

Celery is one of those versatile staples like onion or carrot that finds its way into so many recipes. It used to be a right nuisance to grow – to put it mildly – mainly because you had to plant it in trenches and then bank up the soil around the stems to get those crisp, pale stems. 

Thankfully, modern ‘self-blanching’ varieties do away with all that – so look out for those! Just plant them a little closer, in blocks about 10 inches or 25 cm apart, and be sure to keep plants really well watered because, believe it or not, celery was originally a marshland plant. You’ll need to watch out for slugs, too, because of this.

Have a look at their seeds. They’re almost impossibly tiny! They don’t need to be covered, so sow a meager pinch of seeds into a pot of pre-wetted potting mix, which can be sieved to give a finer particle size. Then, to coax along the seedlings, cover the pot with clear plastic, which will come off once the seedlings have come up. And once they have, these too will go into plug trays – one per plug.

Learn more about growing celery.

9. Sowing Leeks 

Time for the first of this year’s leeks to get sown. The aim is to transplant them around midsummer when they are getting on for pencil thickness and about 8 inches or 20 cm tall. They’re just dug up, separated, and planted into dibbed holes. 

For now, sow two rows of leeks about 6 inches or 15 cm apart in an out-of-the-way spot, or you could sow all of your leeks seeds into one pot of potting mix. Sow the seeds nice and thinly, dropping a couple of seeds every centimeter or half inch, then cover back over to a depth of about 0.5 inch or 1 cm. Water and keep the seedlings moist till it’s time to transplant them.

What are you sowing this spring? Be sure to visit our library of Plant Growing Guides, where you’ll find everything from beans to zucchini – and everything in between!

Also, see our complete guide on how and when to start seeds indoors.

What seeds are you starting this month?

About The Author

Benedict Vanheems

Benedict Vanheems is the author of GrowVeg and a lifelong gardener with a BSc and an RHS General Certificate in horticulture. Read More from Benedict Vanheems

2023 Gardening Club

Tom Chase (not verified)

2 weeks 3 days ago

To convert centimeters to inches, use the conversion factor of 2.54 centimeters per inch.
divide CM / 2.54 or multiply CM x 0.3937
https://www.metric-conversions.org/length/centimeters-to-inches.htm