If you are just starting to grow microgreens, growing arugula microgreens is a great way to start. It is a popular plant among chefs and home cooks, with a spicy nutty flavor that spices up most dishes.
It also grows very quickly, usually harvested in about ten days. The seeds are relatively inexpensive, costing about $15/lb. But you can also grow these greens on a smaller scale and buy seed packets at your local garden store. If you like them, choose a larger volume of seeds for your next purchase.
You don’t need much to grow arugula microgreens – but you can make it more complex if you want. If you’re growing on a production scale, you’ll want to use the recommended items I linked – otherwise, you’ll just be digging around your house and you should be able to collect most of these materials.
When planting, there are three things to do:
Make sure that the surface of your growing medium is flat and smooth
Make sure that you have moistened the soil well
Make sure you use the right amount of seeds
If you are using a 10×20 plant propagation tray, I usually plant about 30 ml (1 oz) of arugula seeds. This gives me a large distribution of arugula seeds on the planting surface. If you are using a different container, look at the image below and photograph for this density level.
You should use at least 1″ of soil or growing medium, but 2″ is recommended if you are going to grow your arugula after 8-9 days. This is when the real leaves start to form and the plants start to depend on nutrition in your soil rather than seed feeding.
After planting, cover the container with something that will block all light. I usually use another 10×20 drawer upside down, but you can get creative – as long as no light gets into the container, you’re good. You need to do this to provide the optimal germination environment for your vegetable seeds.
Every day, open your container and spray your seeds with a spray bottle once or twice. Do not go too far — this is how you get mold. Make sure they germinate well (~3 days for arugula).
Once they have sprouted, keep your growing medium moist by continuing to water. A good rule of thumb is that the deeper your growing media, the less water you will need. They will not use much of this water until day 8-9.
Growth tip: arugula will quickly develop roots and will generate hundreds of small root hairs, which are often confused with mold. Although they are similar, you can recognize the root hairs by their uniform distribution and their grouping around the taproot of your plant.
Somewhere between the fourth and fifth day, your microgreens are ready for the light. Reveal them and move them to a well-lit place. If you decide to leave them outside, you should water more often because of the intense light provided by the sun. If you grow indoors, you don’t need to increase your watering routine much.
To store them correctly, you need to make sure that they are as dry as possible. If you haven’t washed them, they should be quite dry unless you water them right after harvest (avoid this). Personally, I put them in a ziploc bag with a little air in it so that they have room and are not crushed. They will last 7-8 days before wilting a bit, so enjoy them while you can!