How To Grow Microgreens In Trays Step By Step

An easy, step by step tutorial on how to grow microgreens in trays. Includes instructions, what you’ll need, as well as tips on how to use microgreens, details on the different types & nutritional benefits.

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Sproted cress microgreens in a tray. Image: Devi Puspita Amartha Yahya via unsplash.com.
Sprouting microgreens. Image

I love microgreens. They may be tiny – but they’re a powerhouse of nutrients & can add a tasty twist to the most boring of salads! With far more flavour than you might expect from such a tiny plant, you can also use them to garnish soups & casseroles, pop them into smoothies or use in place of lettuce in homemade burgers or wraps. As well as taste good, they also add a lovely pop of texture & colour.

Microgreens are also really easy (and quick) to grow. So, if like me, you’re prone to scrutinising every thing you plant for signs of immediate growth, you won’t have to wait long. Their quick growth also means you can easily generate a constant supply if you plant a batch of seeds every week or so.

What Are Microgreens?

Microgreens are the young seedlings of edible vegetables and herbs, harvested soon after they’ve sprouted ( specifically, just after the cotyledon leaves have developed with one true set of leaves). Microgreens generally take between 7 and 21 days to grow & don’t require much, if any maintenance. You can grow them indoors at home – all you need is a light, sunny spot such as a windowsill.

You can use almost any types of vegetable seeds to grow microgreens, but some commonly grown varieties include cress, coriander (cilantro), broccoli, alfalfa, mustard, mung beans and radish.

Where To Buy Microgreens

Microgreens are readily available to buy online or in garden centres. You may also find them at local farmer’s markets if you have any nearby. Here are a few popular ones you might want to try:

How To Grow Microgreens In Trays

What You’ll Need

  • Microgreen seeds
  • Seed tray (I used old cherry tomato punnets)
  • Compost
  • Perlite (optional but aids drainage)
  • Spray bottle (to water your seeds)

Instructions

Step 1


Fill your seed trays with compost. You want it to to be light & porous – so use a good potting or multi purpose compost that drains well. Some commercial composts can be quite compact, so I find adding some perlite (around 20% of your mix) helps soil stay light & airy. Microgreens don’t require deep soil to grow, so a shallow depth of between 1 to 2 inches works well. Firm the compost down lightly with you hand or the back of a spoon.

Microgreens will grow in almost anything, so if you don’t have any spare seed trays, you can re-use plastic food trays, egg boxes or even yogurt pots. The trays I’ve used below were old cherry tomato punnets.

Step 2


There are many types of microgreens & they’re largely grown in the same way. However, it’s worth reading the seed packet for any special instructions. Some larger seeds, such as mung beans, for example, benefit from soaking prior to use. This helps to soften the shell, aiding faster germination & even growth.

Step 3


Sow the seeds in your seed trays. You can either use your finger to make a shallow drill & sow a dense (but evenly spaced) row of seeds or scatter them evenly across the soil. I’ve tried both below to see which works best. Avoid big clumps of seeds, as this can lead to uneven growth. Lightly cover your seeds with a sprinkling of compost (microgreens need a period of darkness to germinate).

Step 4


Place your seeds on a windowsill that gets lots of light. Aim for a spot where your tray will get an even distribution of light. Water them gently with a mister or spray bottle, then continue to keep your microgreens lightly watered – you don’t want them to dry out. The compost should be moist but not wet. Microgreens are generally ready to harvest in between 7 to 21 days, depending on the type of seeds you’ve used. The leaves are ready when one true set of leaves have grown. Snip the shoots with scissors or pull out complete with the root and use.

Common Problems With Growing Microgreens

Micro greens are really easy to grow with the right soil, light & watering.

However, as with any type of plant, occasionally things don’t quite grow to plan. Truth be known my very first microgreens were a disaster. Too much soil & shade & a choice of seed that could have done with a soak before sowing. If only I’d gone with my own advice & picked radish!

Here are a few common problems below & how best to avoid them:

Slow germination – depending on the seed, most microgreens germinate within a few days. If this doesn’t happen, ensure seeds aren’t exposed. Microgreens need a period of darkness to germinate, so make sure they’re all covered by a thin layer of soil. Another way to speed up germination is to pre-soak the seeds before sowing. Larger seeds in particular benefit from soaking, as it helps to soften their outer shell. Generally, larger seeds benefit from 6-12 hours soaking (or overnight), whilst some smaller seeds may only require an hour or two, to prevent them becoming waterlogged. Check your seed packet for instructions.

Mould or mildew – if you notice mould or mildew growing on your microgreens, the soil is likely too wet, or there’s too much humidity or insufficient drainage in the soil or tray.

Wilting greens – if your micro greens are looking a bit lacklustre & wilting it’s most likely they need more water.

Uneven growth or leaning greens – uneven growth is often down to too many seeds clumped together, whilst leaning greens is often a result of unequal light distribution. Seeds will always grow in the direction of the light source, so if some are in shade, for example, these are likely to grow at an angle towards the direct light. Try rotating the tray or use artificial grow lights to provide a more even distribution of light.

Yellow microgreens – it’s completely normal for microgreens to look yellow at first. This is because the chlorophyll in the leaves hasn’t yet carried out photosynthesis. As soon as leaves receive enough light they should turn green. However, if they continue to look yellow, it’s probably due to over watering or insufficient light.

To Soak Or Not To Soak

When you first start out growing microgreens, it can help to start with something easy, like radish. They’re simple to grow & don’t require soaking (or you can soak for an hour, or so, if you like, to get them started) – simply sprinkle them evenly on soil & follow the steps I’ve outlined above.

However, if you catch the microgreens bug & want to branch out into growing different types, it pays to know which seeds benefit from soaking. As a general guide, it’s best not to pre-soak tiny seeds such as chia, mustard or flax, as they’ll either become gel like (called mucilaginous) or too wet to sow evenly. Larger seeds, on the other hand, (think pea, sunflower & wheatgrass) benefit from soaking, as it helps soften the outer shell.

If unsure, consult your seed packet.

How To Grow Microgreens In Trays Without Soil

I’ve always grown my microgreens in a seed tray with compost. There’s just something about the crumbly, earthy texture I love. However, it’s perfectly possible to grow microgreens in trays, without soil, using a damp paper towel or a material such as coconut coir. GroCycle offer an in depth tutorial on how you can do this. Alternatively, you can try a dedicated microgreens sprouter – these will also grow microgreens without soil.

Types Of Microgreens

A photo of sprouted microgreens in a tray. Image Russ Ward via unsplash.com.
Sprouted microgreens. Image

Since microgreens are essentially the young seedlings of herbs & vegetables, there are a great many types you can grow. There are probably around 80-100 different varieties that exist & you’ll find plenty of these available commercially – other online or in garden centres. However, when I first started growing microgreens, I found it helped to start with seeds that tend to be the easiest to grow.

A few you may want to start with include radish, wheatgrass, broccoli, kale, mustard & clover.

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