Horticulture Magazine

How To Grow Microgreens At Home

mixed microgreens on a wooden background

Microgreens, or micro leaves, as they are sometimes known, are simply salad, herb and vegetable plants harvested much earlier when they are still small.

They are simple to grow and incredibly flavoursome.

If the idea of growing microgreens at home seems a bit alien, don’t worry – this guide will cover what they are and how to grow and care for them.

What Are Microgreens?

radish microgreens with red stems in a small ceramic pot

Microgreens are simply the very young plants of the herbs, salad and vegetables you might normally eat or grow at home, only harvested when they are tiny.

Microgreens are really versatile and can be grown on a windowsill, greenhouse or even outside during the warmer months.

magnified view of radish microgreens

If grown inside, it is even possible to produce them year-round for an endless supply.

It is thought that they were first introduced in an American restaurant as early as the 1980s, but didn’t become more well known until later and the big global business they are today. [source]

When learning about microgreens, it is important to note that they are not the same as sprouts – which can be grown in a similar way, but the difference being that microgreens have true leaves, and take slightly longer to grow before being ready to eat.

Growing various microgreens in a rectangular box

Microgreens are widely available to purchase fresh here in the UK – however, they’re also a great option to grow at home and get children involved in growing their own food.

The process can be a fun and sensory experience and the fact that they grow so quickly helps keep them interested.

Commonly Grown Microgreens

Microgreens can encompass a huge variety of plants in an array of colours and tastes, including herbs, salads, brassicas, legumes and grasses.

The most common ones grown here in the UK, categorised by families include:

Brassicaceae Family
small Chinese kale seedlings

Includes: Broccoli, cabbage, rocket, kale, watercress, mizuna, mustard and radish.

Leguminosae / Fabaceae Family
pea seeds growing as microgreens in a plastic pot

Includes: Pea, broad bean.

Asteraceae Family
lettuce sprouts on a windowsill in full sun

Includes: Lettuce, endive.

Lamiaceae Family
hand holding a plastic container with mint and lemon balm

Includes: Mint, oregano, basil, lemon balm.

Poaceae Family
wheatgrass microgreens in sunlight in a green plastic pot

Includes: Wheatgrass.

Some microgreens, such as mizuna and rocket can be a bit spicy, even bitter and others like basil almost sweet, so there is something for everyone’s taste buds.

How To Grow Microgreens

1) Fill Your Containers

plastic containers filled with a linen substrate

Microgreens can be grown in almost anything, from seed trays and yoghurt pots to lengths of guttering.

The containers do not even have to have drainage holes, but this can help.

To grow microgreens, fill your container, almost to the top, with a fine-grade compost and gently tamp the soil down.

You can also use a linen mat as shown in the example above.

2) Sow Your Seeds

radish seeds being poured out of their packet onto the substrate

Unlike when growing ‘normal’ sized plants, microgreen seeds can be sown rather thickly.

This is because the shoots are going to be harvested much sooner and the plants are not going to grow large and compete for space.

Once the seeds are sown, press them down gently.

3) Water Your Seeds

a spray bottle being used to water the seeds in their container

Water with a spray bottle ensuring the seeds and compost are moist.

Using a spray bottle, rather than a jug or watering can, is a gentle way of watering and will reduce any likely hood of the seeds being dispersed.

It is often recommended to soak the seeds overnight, prior to sowing, to speed up germination, but this is not strictly necessary as they are such a quick-growing crop anyway.

4) Place In A Warm, Sunny Spot

germinating radish seeds visible through their transparent container

For the seeds to germinate, place the container on a sunny windowsill, south facing is ideal and remember to keep the soil moist.

In the right environment, the seeds should germinate within 2 – 3 days.

Having germinated, the microgreens need light to continue to grow.

A sunny windowsill is more than adequate usually, but lights, such as LED grow lights can be used, especially in winter when light levels are at their lowest.

Continue to keep the seedlings well-watered, but don’t overdo it, as overwatering can lead to problems, including mould growth.

5) Replenish Your Seeds!

arugula seeds in their packet

If you get the bug of growing microgreens, it can be surprising how quickly you go through seeds!

Thankfully seed can be purchased online in bulk bags of 500g or more, which is more cost-effective and should keep you in microgreens for a while.

Even old vegetable seeds found in the bottom of the garden seed tin are worth a go and often work well.

arugula seeds in a heap on a linen substrate

This is especially true of brassicas – the seeds are so small and there are often many left to be found at the bottom of the packet.

It is possible to have a continual supply of microgreens, rather than a large glut, through a process called successional sowing.

This isn’t as complicated as it sounds; it simply means sowing a new batch of seeds every week, so that as one batch has been harvested another one is growing on and almost ready.

6) Harvesting Your Microgreens

fully grown radish microgreens ready to harvest

Once the plants are about 5 – 7.5cm tall and usually after 2 – 3 weeks, the shoots are ready for harvesting.

The main thing is that they have developed their true leaves.

To harvest, simply cut just above the substrate with a clean and sharp pair of scissors or snips and enjoy.

hands using scissors to harvest microgreens

Microgreens are best eaten fresh and one of the great things about growing microgreens at home is that you only need to harvest what you need then and there – the rest will happily continue to keep until you next need them.

Some microgreens will regrow, especially if cared for and if cut just above the lowest leaf.

If they don’t or if you would rather sow a fresh batch, the old soil can be composted and you are ready to start again.

Common Problems

Why Are My Microgreens Falling Over?
extremely leggy microgreens shown falling over

Microgreens falling over can be a rather common problem when growing at home and there can be several causes.

Lack of water is possibly the most common reason, so try giving them a good drink and see if they recover in a few hours.

But do water gently as the pressure from a jug or tap can force them over as well.

Another potential cause of them falling over is because they have grown too thin and leggy and subsequently become weak.

This is often because they have not received enough light and may need to be moved to a sunnier spot or placed under a grow light.

Why Haven’t My Seeds Germinated?
cabbage seeds on a wet mat

Seeds might not germinate for a number of reasons, including the seeds being too old, of poor quality or not being in proper contact with the soil.

Germination usually only takes a few days, so any longer and it might be worth checking the sow by date of the seed packet or trying a different brand if it continues.

It’s important to remember that seeds need good contact with the soil, the right temperature and to be kept moist, as poor germination can often be caused by just poor soil contact, being too cold or being allowed to dry out.

Why Is There Mould On My Microgreens?
magnified view of root hairs on germinating seeds

Mould on microgreens can sometimes be confused with white root hairs, which are usually nothing to worry about and often disappear in a few days.

If the white substance around the base of the seedlings does not look hair or feather-like, then it is most probably mould.

Mould is most often caused by poor drainage, so if you are using trays or containers without holes, it might be worth trying one with holes, to allow excess water to drain.

High humidity can also encourage mould, so opening a window or placing the seed tray in a more ventilated space may help.

mould on germinating microgreen seeds

A lack of light can also be the culprit so increasing the available light may help prevent mould.

Using a soil or compost which does not have good drainage may also contribute to mould growth.

A freer draining compost mix could be tried or even adding some perlite to the compost mix may well help.

Lastly, it is really important to practice good hygiene and clean the trays and containers thoroughly after use and allow them to dry before stacking and putting them away until next time. 

The best course of action against mould is to try and prevent it in the first place, as if your microgreens do unfortunately get mould, then it is recommended not to consume them.

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