Growing microgreens on wool cool
Microgreens are an easy way to grow salad leaves. They’re especially useful when salad plants aren’t growing well outside (both the middle of winter and summer can be tricky times) and for those who don’t have a vegetable garden. Microgreens are either grown in seed/potting mix or hydroponically (in water). If growing them hydroponically the seeds need to sit on some sort of mat e.g. paper towel. Woolcool works perfectly. Woolcool is the material you’ll be finding more and more in packaging – often used to insulate food deliveries. It’s made completely from wool and breaks down well in the garden or when composted.
What are microgreens?
You may have heard the term but aren’t familiar with what they are. Microgreens are just that – tiny greens (well, sometimes red too). Seeds of vegetables and herbs are planted densely and the leaves are snipped off and eaten when still small. They’re the same seeds you would use to grow into a regular sized plant but because they’re harvested early, they often don’t resemble the parent plant. Rocket, mizuna, radish and beetroot are commonly grown as microgreens.
Why grow them?
- Microgreens suit people who don’t have a vegetable garden but still want to grow their own tasty produce.
- They are very tasty and supposedly nutritious. I can’t find evidence to back this up but they certainly aren’t bad for you.
- Microgreens are extremely quick to grow – some, like rocket, will be ready for harvest in two weeks. I guess that’s why it’s called rocket!
- If you buy microgreens to eat then of course growing your own is cheaper. You can also control the level of organic-ness they’ve been grown by.
How to grow them?
As I mentioned in the open, seeds are either grown in soil (seed raising or potting mix) or hydroponically.
I’ve grown them in a mix of potting mix with seed raising mix just on the top but for me that isn’t idea. I like to have the microgreens on the kitchen window sill where I can see them every day to keep them watered and also have them close at hand to use in a meal. I don’t like having potting mix in the kitchen because it can easily get knocked over.
How to grow microgreens on Woolcool
For those who learn by watching, I’ve now made a video which I hope helps. Scroll to the bottom to see the You Tube link
To grow microgreens on woolcool you’ll need –
- a container
- microgreen seeds
Chose a container. This could be a container specifically designed for growing microgreens or something re-purposed eg a plastic takeaway container or baking dish. Ideally you want the piece of woolcool to be slightly raised out of the water. Do this by –
- Using a purchased sprouting dish as in my photo bottom left
- Sitting the wool cool out of the water on some mesh
- Jacking the wool cool up with some pieces of timber or similar
If you can’t find a way to lift the woolcool out of the water then let it sit in a shallow dish. Don’t worry, I’ve grown it like this, as in the middle photo above, and it’s fine. Use two layers instead of one and be diligent with keeping the water fresh. Note – the container doesn’t need drainage holes.
Cut the woolcool to fit your container. I’m not going to tell you how to measure and cut. Scissors, blade, ruler, eyeball it. It doesn’t need to be perfect.
Soak the woolcool. Rather than use it straight away it’s preferable to soak the cut piece(s) for 24-48 hours in a large dish. Change the water twice a day. Ideally, you’ll have soaked and changed the water four times. Don’t panic if you don’t do this – it’s not going to affect how the seeds grow. It’s made from wool and after a few days the family will be complaining of a weird wet sheep smell in the house. Soaking it before spreading seeds on it helps prevent this. Take it out of the water prior to spreading the seeds on it.
Prepare the seeds. Work out how much seed you need from the packet(s) you’ve got. The packet should tell you how dense to sow them – it’s much denser than sowing them in the garden.
Sit the moist woolcool in your container of choice.
Spread the seeds over the woolcool.
Mist with water.
Cover loosely to keep light out and help retain water. Use something like a piece of cloth, paper towel or plastic bag. The seeds will stick to anything directly on top of them so the cover should be over the container not sitting directly on the seeds.
Position your tray of seeds somewhere suitable –
- With adequate warmth (not outside).
- Where you’ll remember to check on it once or twice a day.
Mist with water once or twice a day to keep moist.
Seeds sprouting? Once the seeds start sprouting, remove the cover. Depending on the variety of seed this could be in just a few days.
If you haven’t had them sitting somewhere with adequate light, now’s the time to move them. Adequate light means something like a windowsill. Mine doesn’t get all day sun but is fairly well lit. If you’re in a situation with little light you might need to move them during the day in order to get the morning then afternoon sun or use artificial light. Growing microgreens is similar to growing a potted herb or plant so you’ll probably know if you’re in a situation where you struggle with enough light.
Add water. Once the seeds have started sprouting misting them probably won’t be adequate. Add water to the container. Pour water gently around the edge of the woolcool rather than tipping it over the seedlings. Don’t let the seedlings drown in water – just the roots will want to be wet so fill the container up to the base of the woolcool. (If you have it sitting directly in a container put in enough water to keep the material moist rather than water logged).
Change the water daily. If you’ve used a container with the woolcool above and water below as in my tray then it’s easy to lift the tray, tip out any water, rinse the tray and put in fresh water. If you have the woolcool sitting directly in a container you can still very gently rinse them by tipping out any excess water and pour on fresh water. Do this gently as some seeds may not have sprouted yet, especially if using a mix of varieties.
Feed. After about a week start giving the growing microgreens a weak liquid feed every two or three days. They don’t need much and the size of your container will influence how much you need – around 60-100ml.
- I use a liquid seaweed product, diluted to the instructions. 500ml (1/2 litre) only needs 1.5ml of product (not much!). I would only need about 60ml of this every other day so I usually mix about 500ml, use some and put the rest in the garden or pot plant.
Change the water, rinse out the tray and put in fresh water before applying the liquid feed. Pour the feed over the base of the woolcool and seedlings rather than over the leaves.
Harvest. Which variety you have will determine when they’re ready. Some will be ready in 8-10 days. Leaves are usually harvested when they’ve reached the ‘true leaf’ stage but let your taste buds guide you – taste the leaves and start eating them when you like the taste. Cut rather than pick the microgreens as they are easily pulled up and damaged. Cut above the roots leaving some stem. If the timing is right when you cut them you may get a second flush of microgreens but the leaves don’t usually grow as strongly as the first ones.
Repeat the process. Start a second tray a couple of weeks after your first tray so you can keep a continuous supply going.
You can re-use the woolcool but I find it’s starting to get manky after a couple of weeks as it’s been constantly wet. If you’ve grown and eaten them quickly this might not be the same for you. The used woolcool can go out in the garden as mulch or in the worm farm or compost bin.
Have you tried growing microgreens using this or a similar method? I’d love to know how it went.
For those who learn by watching – I’ve now made this video which I hope helps.