Microgreens are tiny versions of the adult vegetables and are harvested during the seed leaf stage. We consume them at this stage because they are packed with the most amount of nutrients. Microgreens are really one of the easiest greens to grow and offer a high germination rate.
I am often asked:
- What is the best medium to grow microgreens?
- Can I re-use the medium after I have harvested my microgreens?
- Do I need to add any fertilizer to my microgreens?
Let me answer each of the questions above individually.
Best Medium For Microgreens
When growing microgreens, always look for a germination mix with a loose, light texture. It should preferably be soil-less. A peat based mix (either coco peat or peat moss) with vermiculite and perlite works best. Commercial garden soil varieties are not the best medium for microgreens because they are too compact and don't allow the roots to penetrate and grow. Since microgreens are harvested at the seed leaf stage, their roots and stems are still fragile. A peat based mix is light and loose, allowing the roots to easily grow in the medium.
Re-Using Your Medium After Harvesting
Most commercial microgreen growers do not re-use their germination mix (at least not immediately) after harvesting. This is because the mix will have stems/roots and ungerminated seeds from the previous sowing which will interfere in the growing process of the new batch of seeds. Also, the mix may loose some of its nutrients which would have been absorbed in the first sowing. Many commercial growers recycle their mix by composting it in a container for at least a month before re-using the mix.
For home growers (who are usually not fussy about the purity of a particular crop of microgreens), it is possible to reuse your mix but you would have to ensure that the stems and roots of the previous crop is removed. This can prove to be difficult if you are growing larger seeds like sunflower and peas because the roots of these microgreens tend to grow deeper.
So though you can reuse your mix, the safest thing to do is to use a fresh batch with every new sowing process.
Do I Add Fertiliser To The Microgreens?
No, because microgreens get all the nutrients they need to grow from the seeds. Since they are harvested at the seed leaf stage, you shouldn't add fertiliser to the germination mix.
Check out my video on what you can do with your used potting or planting mix after harvesting your microgreens.