When to plant tomato seeds

You can soon be on your way to enjoying your very own home-grown tomatoes.

when to plant tomato seeds

by Emily Gilbert |
Updated on

If you’re looking for something easy to grow, growing tomatoes from seeds is a great place to start, whether it’s in a hanging basket, greenhouse or even in your flower border.

With just a couple of plants, you can be on your way to enjoying your very own home-grown tomatoes for your meals. To get you've started, we’ve pulled together everything you need to know about planting tomato seeds.

When do you plant tomato seeds?

It’s easy to grow tomatoes from seed sown indoors in warmer conditions. In terms of the growing season, if you want to grow tomatoes outdoors, you can sow from late March to early April but if you want to grow your seeds indoors or in a greenhouse, you’ll need to start sowing earlier, from late February to mid-March.

Tomato varieties

There are four main types of tomatoes but did you know there are over 10,000 different tomato varieties?

Here are the most popular ones:

Cherry tomatoes - Small and sweet tomatoes

Medium Tomatoes - Known as salad tomatoes, a good all-rounder.

Beefsteak Tomatoes - These big tomatoes often weigh 200g or more. They have a meaty texture.

Plum Tomatoes - These tomatoes have an oval shape. They are very fleshy and have fewer seeds.

when to plant tomato seeds

Sowing tomato seeds

When purchasing, be sure to check seed packets or plant labels to make sure that you get the right type to suit the space you have to grow your tomato seedlings.

According to RHS, tomatoes tend to have two different ways of growing:

• Cordon (or indeterminate) tomatoes grow tall, reaching up to 6ft, and require support.

• Bush (or determinate) tomatoes are shorter and bushy, and don’t require staking.

Here’s some advice from our friends at Garden Answers on how to sow tomato seeds:

  1. Fill a small pot with compost and sow seed thinly across the surface. Sprinkle lightly with seed compost, label and water with a fine hose. Keep them warm.
  1. Place on a heated mat, inside a windowsill propagator or in an airing cupboard (check daily for signs of germination). You’re after 20-25C (68-77F).
  1. Keep them warm and bright, rotating windowsill pots daily. Prick out into individual pots once they have their first true leaves.

Between germination and planting, keep young plants growing as smoothly as possible. Keep temperatures above 15C, and certainly not below 10C as frost is lethal.

Each time their roots fill a container, repot the tomato, planting deeply. New roots grow from the buried stem encouraging a strong, stocky plant.

If you don’t have the space to grow from seed or are simply a bit impatient, you can buy young plants from your local garden centre in the spring.

How much water do tomato plants need?

You will need to get your watering can out regularly as tomato plants do need a lot of water and feed so for best results, you’ll want to water your tomato plants little and often.

When should you harvest tomatoes?

Understandably, you’ll be excited to try your tomatoes as soon as possible and the good news is that you can pick your fruits individually once they are ripe and fully coloured.

Related: Why tomatoes are so good for your brain!

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