Microgreens are one of, if not my favorite, recommendation for people to grow. They are so easy, so fast, and so nutritious. AND you don’t need a garden or outdoor space to grow them. They can be completely grown indoors in a sunny window. Microgreens are basically baby plants that are harvested once their first true leaves appear (usually when they are 2-4 inches tall). At this stage, they are more nutritious than the fully grown plant and are an easy way to add extra greens to your smoothies, salads, sandwiches, or used as a garnish. Not to mention, they are wonderful to grow with kids given their easy care and it only takes about 2 weeks until it’s time to harvest. Microgreens can cost anywhere from $20-$50 per pound so it is definitely more cost effective to grow your own.
- Soil mix
- Shallow tray
- Microgreen seeds (there are so many to choose from, but common ones include:
- Pea shoots
- Salad greens
- Wheat Grass
- Spray bottle
- Kitchen scissors
1. Container: I usually use a large tupperware/plastic container, but some might prefer to start off with a smaller take-out size tray. Anything that is about 2-3 inches high and can hold water will do fine. You could use an old oven tray too. A good tip is to add water to the container before adding the soil, since then the soil will wick up the moisture without needing to heavily water from above and displace seeds when planted.
2. Soil: I’ve tried everything and have honestly not seen too much of a difference. You can use seed start mix (more expensive), fine grain potting mix, or coconut coir or a mixture of different mediums. The goal is to have something that isn’t too bulky so it’s not hard for the seeds to emerge or develop roots. I’ve even used thicker garden soils with chunks of bark and such at the bottom of my tray, and then a finer covering of coconut coir or seed start mix at the top which worked fine. Even straight up coconut coir which does not contain many nutrients works fine because the plants will be harvested before they lack nutrients.
3. Filling the tray: Don’t fill all the way to the top. They really only need about an inch of soil, but I usually fill higher than that if I have the room. Make sure to pat the soil down before spreading the seeds.
4. Seeds: There are many seeds to choose from and your choice depends on what you want to use them for and your personal taste. If you’re planning to use them mostly for smoothies, maybe avoid the spicier varieties like mustards, and stick to milder greens. Also keep in mind growing rates. You don’t want to plant things together that have very different growth rates since that will make harvesting more difficult. The goal is to have them be similar height when snipping off for harvesting.
5. Planting: Since microgreens won’t be growing for long, they don’t need much space so you can basically spread them evenly all over the top of the soil without being concerned about spacing. You don’t want to pile them on top of each other, but the seeds can be very close together. Then simply cover them with a very light layer of soil on top. Some people actually just use a dark lid to tamp them down and leave the lid on top of the seeds until they germinate and require some light. The tray provides the darkness needed for some seeds to germinate and helps to retain moisture. I prefer to cover them lightly with soil, but to each their own.
6. Water: Since you hopefully added water to the tray prior to adding your soil, then your soil should be moist already. You’ll simply need to mist the top of your tray until damp. To be honest I haven’t always misted. I’ve watered with small watering cans and haven’t had an issue. The only time I did have some mold grow was when I forgot to take a lid off for several days. Seeds don’t need light until after leaves have sprouted and many seeds germinate better in darkness. I recommend checking the moisture level every day and giving them a spray/light watering as needed.
7. Light and temperature: I’ve done many variations of light and heat exposure. I’ve kept them completely inside in a south facing window and kept them covered with a clear lid until germination…worked out great. I’ve kept them inside on a temperature controlled heat mat with less sunlight and they were a bit leggy, but otherwise fine and I didn’t notice a big difference in germination rates based on temperatures. I’ve kept them outside in the sunshine during the day and brought them in at night based on lower temperatures and they did great. I’ve kept them outside in partial shade the entire time, and still great. It’s hard to mess these up =). Even those with a self-proclaimed black thumb will find success.
8. Harvesting: It’s tempting to harvest as soon as you see leaves, but those first little leaves you see are called cotyledons and are not the first true leaves. Wait till the leaves that show up after the cotyledons appear to harvest. Another great thing about growing microgreens instead of buying them is that you can cut and come again. You don’t have to harvest them all at once simply because the first true leaves appeared. You can trim exactly as much as you need for your smoothie or sandwich and come back for more later. Simply trim above the soil line and use the entire plant.
9. Disposal: After growing you’ll probably not want to use the soil again. With that many plants, however small, they will have used up any nutrients available in the soil and it will be spent. That doesn’t mean you should throw it out though! It’s wonderful for worm bins and compost bins. Or you can simply bury it in your yard and it will eventually break down too.
10. Common Problems:
- Mold: I’ve only had this happen once when I kept a tray on too long as mentioned above, and I simply put it out in the sun and avoided the tiny section and made sure to rinse the nearby areas well before using. I’ve also heard that grapefruit seed extract can be used as a natural antifungal to spray on any mold areas. If the mold is wide-spread throughout your microgreens it’s time to toss it all in the compost bin though and try again.
- Leggy Microgreens: Not enough sunshine. Find a south facing window or give them some time outside in the sun.
- Pests: Honestly never had an issue even when I left them outside the entire time. I think I found some nibbled leaves before, but that’s common with anything you grow. Just give it a rinse and enjoy.