How to Grow Microgreens - a complete guide from Microgreen Experts: On The Grow
Okay, you're ready to dive into the amazing world of growing microgreens at home or for the purpose of starting a microgreens business of your own - to learn how to grow these amazing greens, you can start by reading this blog which will help you get the gist of it, but if you really want to learn EVERYTHING we have learned from 2019 to 2021 we highly suggest our book "Becoming a Microgreen Master" - it's basically the ultimate Microgreen Growers Manual.
But any who, let's help you learn the basics! Before we can start growing beautiful microgreens like these Speckled Pea Microgreens, you first need to choose how you are going to grow and determine what materials you will need to start growing with. Then we can walk through each step of the way to get you growing healthy, happy, and abundant trays every time. We hope that this article can become your go to guide on how to get amazing grows, so let’s get started!
Choosing grow medium
The first thing we are going to do is select a growing style! Here at On The Grow, LLC, we love basically all growing methods! As long as it is something you enjoy and produces happy microgreens, we are all for it!
If you're growing microgreens in soil, they will have access to all the minerals and organisms in the soil, immediately. Using soil is a tried-and-true method for growing and will generally provide really solid results, depending on the soil used. When it comes to growing with soil, we prefer to use soil that doesn't have chunks of wood or other large debris while having good drainage. We usually stick to "seedling mixes" or "potting mixes" if no seedling mixes are available. A popular soil choice within the commercial growing community is ProMix+ HP Biofungicide Mycorrhizae.
We love to grow microgreens "hydroponically" which is basically adding minerals to water and giving that to the plants instead of using a soil that has minerals added already. To grow hydroponically, you must...
First select your grow medium, we prefer Coco-coir because it gives us such great results and we have more control over it because we can choose to boost our plant growth by adding our own nutrient's. What makes it even better is even without nutrient's Coco-coir grows microgreens perfectly! Coco-coir is made from the outer-husk of a coconut and is a great sustainable option for growing. We buy our Coco in compressed bricks and expand them with water when we need it!
Choosing grow trays
Next step is to select your Trays to grow in. We use a 3-tray method that consists of 2 shallow no holed 1020 trays and 1 shallow slotted or mesh 1020 tray. You can also get away with using 2 trays (one no-holed tray and one mesh or slotted tray).
If you are wanting to get started without buying trays, you can practice growing on plates or old food containers to hold the grow medium and seeds. Click here to see our video on this!
Can't decide if you should use a Mesh tray or a Slotted tray? Usually we will use Mesh Trays whenever growing on a Hydroponic Grow Mat as the medium, because the roots can latch onto the mesh holes making it easier to harvest later. If we are using Coco-coir or a Soil medium we like to use a Slotted Tray, that way we don't lose to much medium through the mesh holes...but mesh trays also work great for Coco-coir and Soil too.
Tip- keep the coco or soil moist when using a mesh tray so it doesn't fall through.
Choosing Microgreen Seeds
Lastly choose your seed. Some great varieties for beginners are Broccoli, Purple Kohlrabi, Turnip, Radish, Mustard, or basically anything within the Brassica family. These crops grow abundantly and are easy to grow, especially for new growers.
Tip- we have tons of Full Walk-Through Grow videos available on our YouTube (by clicking here) that can help guide you through growing different varieties for Free and with ease! Also be sure to check out our Free Downloadable Microgreen Grow Guide on our website's product page to learn about how much we use of each seed and our average grow times! If you're looking for a seed company, a reliable seed source is TrueLeaf Market , which is one of our go to seed company choices.
Now that we have our materials it is time to start growing!!
First, take one of the no holed trays and place your Slotted or Mesh tray on top of it, so they fit together like the picture on the left... (there's a black tray under the green)
.... Second, fill the Slotted or Mesh tray with the grow medium of choice. Typically, we use about 6-8 cups of coco-coir per 10x20 tray. That way it fills the tray enough to cover the area, but the grow medium is still just below the rim of the tray. Evenly distribute the grow medium in the tray so that you have a nice, leveled surface! It does not have to be perfect, just make sure you do not have a lot of low or high spots as it will cause problems later. If you run into clumps of grow medium, try breaking them apart some.... (You can also use another tray to press it down even)
...Third, take your desired seed and evenly spread the seed on the tray. Typically, if we are seeding a 10x20 tray of Broccoli Microgreens, we will use 25grams of seed, but if we are using a 9.5x11.75 tray will cut the sow weight in half. Keep in mind that the seed amount will change depending on the Microgreen varieties you pick. You want the seeding to be dense, but not so densely that you restrict the air flow between the plants. If a tray is over-seeded, it will have a much higher chance of developing problems with mold! But like I stated before, you are in luck because we have our wonderful Grow Guide here on our website and Full Walk-Through Grow videos on YouTube to help you easily figure out how much seed to use for a lot of different varieties of microgreens!! **When it comes to seeds with a harder shell, like Beet Microgreens or Swiss Chard Microgreens will put a thin layer of coco-coir across the top of the seed as well to help with the germination and seed hull removal. Check out our video on How to Grow Swiss Chard Microgreens if you're interested in the full process!
Caring for germinating Microgreen Seeds
You have seeded your first tray, Congratulations! It is now time to give your seeded tray a light mist with either a spray bottle or a water hose that has a spray attachment set to the 'mist setting'. Making sure not to over-saturate it (you don't want puddles or water pooling in the bottom of the tray!) but give it enough water so the seeds can happily germinate!
After watering, you take your second no-holed tray, place it on top in the same orientation as the other trays (that way it makes contact with the seeds) then place some weight on top of that tray before you place it onto a dark shelf to germinate.
You may be asking "Why do we add weight?"... The reason why we add weight is for a couple reasons. Adding weight helps you get even germination across the tray because of the pressure it puts on the seedlings, while pushing them into the moist grow medium. The weight also helps remove the seed hulls by providing resistance which is extremely important, especially for crops like Sunflower Microgreens. However, there is a limit to how much weight you should use along with some varieties that do not do well with added weight, like Red Garnet Amaranth Microgreens. For most crops we will use between 15lbs to 7lbs of weight. Then for the more delicate crops, will use just the empty top tray to act as the "weight". If you feel confused on which crops need added weight and which crops only need an empty tray, we have that information listed on our grow guide! (We've found that all crops will grow without weight, just not as well as with-weight.)
Alright, we have gone through the steps for germination. Now what?
What you will want to do is, twice a day for the first couple days, lightly water your seeds in the morning and night with regular water, that way they can continue to germinate. After each misting be sure to place the top tray and weight back on top before placing them back on to your shelf.
After a couple of days, you will see that the crop has germinated! Keep in mind that germination time is different for each variety. Some happen within 1 day and others take up to 3 days.
There are some crops that can take up to 15-20 days to germinate, and we avoid those crops. Ain't nobody got time for that.
Whenever 1-5days has passed, you may see that your tray has germinated well (you want plants that have removed the seed hulls)! That means it is time to move into the next step which is Black-Out! But before we move into Black-out, below are a few tips if you've run into anything unexpected during your grow.
Tip 1 - your seeds may take more or less time to germinate depending on the grow medium you selected and the climate in which your growing in. We know that we get the best germination when we use Coco-coir and grow in our set Climate of 75-85F with a humidity of 50% or lower. When we have grown in temperatures below 75F, we notice slower germination and growth. Something else we highly suggest is having good airflow, as this will help with preventing Micro-Climates on the shelves created by heat from the lights and will reduce issues with Mold. Every shelf in our grow space has one of these fans per-shelf, and if your curious on how we setup our grow racks be sure to check out our video (click here).
Tip 2- Something you might notice now that your seeds have germinated is some fuzzy white stuff, most people confuse this with mold… but do not worry! Those are called "Root Hairs" which are just part of the plants root structure. If you picked a seed like Radish or other Brassicas… they tend to form a lot of them. How you can tell Root Hairs apart from mold is, by looking to see if the "fuzzy stuff" is attached to the plant? Or is it attached to the seeds and/or grow medium? If it is attached to the plant, then it's most likely Root Hairs. However, if the white strings are coming off of the unopened seeds, seed hulls or grow medium and has a Spider Web or Spore look to it… then that’s mold and you may have over watered or seeded to densely. No worries though! As long as you caught it before it goes crazy, your good. Try watering a little less on your next watering, and you can spot treat the mold with a 2tbs 3% Food Grade Hydrogen Peroxide per 1 Liter of water mixture to combat the issue! Good airflow can also help reduce or control mold.
Now it's time to put your crops into Black-Out. Remove the weight and reverse the top tray so that it is upside down and creates a "dome". What this will do is block light from getting to your crop, allowing the plants to try and stretch their way up to find light... thus making your crop taller and easier to harvest when it gets to harvest day. Generally, we only do a 1 to 2-day Black-Out period for most crops, because you do not want your crop to get too stretched out or it becomes lanky. There are a few crops like Shiso microgreens that do better with a longer blackout period such as 3-days. This is because shiso microgreens stay very short making them hard to harvest if you do not stretch them for longer. Again, we have this listed on our Grow Guide for you! Remember to mist your crop twice a day with regular water, once in the morning and once at night during the Black-Out Period just like we did when it was under weight. Once you've misted the crop, place it back on the shelf.
LET THERE BE LIGHT! After 1 to 2-days have passed with your crop in Black-Out, they should be ready for light! Now it is time to remove the dome and introduce them into that sweet light that they have been searching for! At this point you'll start to see your crop transform from Yellow to Green within a few short days. The lights we like using and suggest to others are 20watt shop lights, and we use 3 per shelf. You can use Natural light if you do not have lights available to you, just be sure to put your tray near a well-lit window. If you are using artificial lights, like we are then stick to an on/off period of around 17 hours ON and 7 hours OFF. This lighting schedule for microgreens has been working great for us over the past year. Check out our Light Experiments on YouTube if you need help picking some lights for growing microgreens!
Bottom Watering Microgreens
Our rule of thumb at this point is any time we introduce a crop to light, that is when we begin bottom-watering. We bottom-water microgreens by adding water into the no holed tray that is underneath the slotted/mesh tray. This is also when we start adding Hydroponic Nutrients that are mixed into the water which we PH balance to the 5.5-6.0 range. We start bottom watering with a low amount of water, usually 1/4 cup twice a day. Then we over time bump that up to about 2-3cups of water, twice a day, as they need it. Generally, you can tell whenever they need water by checking the grow medium, does it look or feel dry/saturated? OR if the crop is falling over after being removed from blackout, that can also be a sign of under-watering… So just be sure to pay attention to what your crop is telling you! If you run into issues with Mold or Fungus Gnats, you may have seeded to densely or over watered, next time just make some adjustments to your grow.
Tip- we use this same watering method for Soil, we just don't use nutrients with soil. Only PH balanced water at the 5.5 to 6.0 range is needed. Don't know how to PH balance your water or mix nutrients? Check out this video (here)
7 to 13+ days have passed of you watering your crop twice a day, and now you are looking at a beautiful tray of microgreens that YOU GREW!! Deciding on when to harvest your microgreens can be as easy as checking out our grow guide to see when we generally harvest or looking for the signs that their telling you "hey I'm ready!". The best ways to figure this out is to check between the Cotyledon's which are the first set of leaves you’ll see from a germinating seed and check if you can see the true leaves emerging between the cotyledon's (generally whenever you see signs of True Leaves that means it's time to harvest your crop). If you wait too long after true leaves start to show, the crop may begin to develop a bitter taste. Crops like Orach, for instance, are better whenever they have a more developed true leaf.
Tip- If you are not sure about what day to harvest on, simply pull out a Microgreen or two and give it a taste test! This way, you can figure out if you enjoy the flavor or not before harvesting.
Well, y'all, that is How You Grow Microgreens using the On The Grow method! If you have any questions, be sure to check out our YouTube channel where we have tons of in depth Full Walk-Through Grow Videos for various crops along with many other videos to help you learn more about microgreens!
Happy growing & keep on Be-Leafing!
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-------------------------Written by: Mandi Warbington
Edited by: CJ Vaughn
Published: July 27,2020
All content shown is Property of On The Grow®, LLC
Hi, I purchased a hard copy of your book so that I could have all information in my hands, and appreciate all of the hard work you put into it. Unfortunately, I have searched and searched, and cannot find the seed growth density guide nor the downloadable PDF grow / seeding guide that are referenced and said to be available here on your site.
Where do I find your downloadable grow guide?
I am wanting to buy your stainless steel grow medium and your downloadable grow guide. I can not find it on your website.
Please help. Thanks