Lesson 3: All About Microgreen Trays

Tray Terminology

Any container that will hold potting soil will grow microgreens. The containers can be of any size and shape. However, there are a few things to keep in mind.

1. It is best to have two trays. One tray that does not have holes.
   This is what I call the Watering Tray.
2. The second tray should have holes in the bottom. This I call the Planting Tray.
   The holes should be small enough so potting mix does not fall through them.
   The holes should be evenly distributed across the planting tray bottom.
3. Although not necessary, it is better if the trays fit snuggly together. When a planting tray is lowered into a watering tray a snug fit will force water up into the soil rather than counting on the potting mix to draw water up against gravity.
4. Using tray sets with the same dimension is beneficial. Using the same size trays simplifies the process. Instead of having several trays of different sizes and always having to remember or look up how much soil and seed you need, one tray size will make it easier for planning and watering.
5. Heavy-duty trays are much easier to handle than buying thin plastic trays that will bend and break. Small trays less than 10-inches on a side can be made of thinner material. But larger trays make it easier to move the tray around without risking it breaking or dumping out microgreens after you have grown them.

Recommended Microgreen Trays

The Home Microgreens Trays

The dimension of these trays is around 8″ by 5″ by 1-13/8″. The tapered sides uses less soil and the holes are very evenly distributed across the tray bottom.

The small surface area allows air to easily circulate across the width of the tray. I find these trays are easier to grow microgreens than larger trays because of the smaller width allowing better air flow and more light to the microgreens in the middle of the tray.

The small size is also ideally for growing a new variety to see if you like it before buying a large quantity of seed; or for those varieties where you don’t need many microgreens to effect the flavor of food like onions or any of the herb microgreens.

The Home Microgreens trays come individually, as a set, or as a set with soil, or as a “Kit Lite” that also contains a seed packet of your choice.

Heavy-duty 1010 Trays

The number on standard trays refers to the “size in inches” of the tray. That is in quotes because they aren’t true 10 inches square. Depending on the manufacture the size can vary, usually a little smaller than 10 inches square.

The 1010 trays I sell are from Bootstrap Farmer and are very heavy duty. Also shown are tray separators (they come in sizes for HM trays and 1010 trays. More about them in a little bit.

Recommended products

Heavy Duty (shallow) 1020 trays

The 1020 trays are the size you see in garden centers, and like 1010 trays they aren’t quite 10 inches wide by 20 inches long. But they are close.

What I didn’t mention in the video is that you want to buy the shallow trays. Sometimes called microgreen trays or germination trays. Microgreens do not need a deep tray. Half filling a tall tray with half as much soil makes it much harder to harvest and reduces air flow across the microgreens.

Trust me, it is much easier and better to use shallow trays.

I do not carry 1020 trays (currently) because they are difficult to ship. The boxes are expensive and if only one or two trays are bought it doesn’t cover the cost of the box and postage. Plus, Bootstrap Farmer sells them in 2 packs and they can ship them to you much cheaper than I can.

Bootstrap Farmer also sells internationally.

Tray Separators

The tray separators are a handy piece of equipment to have. They block light and can settle down across the whole width and length of a tray (you will learn why this is important in a later lesson).

The Home Microgreens Trays come with a lid that is opaque and not as good as the tray separators, which are made from corrugated plastic (coroplast). You can make your own fairly simply. Sheets can be bought at hobby and office supply stores in 20″ by 30″ sheets.

They are a pain to cut, and that is the reason for the cost of mine. It takes time and of course shipping weight. So I leave it up to you whether you make your own or buy them.

Why Not Use the Bottom of a Tray as a Separator?

I don’t like to use the bottom of another tray in the process you will learn fairly soon because it gets the bottom covered in moisture and seed hulls. So when you set the tray down it makes a mess.

The tray separators are easy to wipe off as they are smooth with no grooves. The edges of the tray also support the weight so there is enough pressure to make contact with the seed and soil but not the full weight of what you are using.

If you haven’t a clue in what I’m talking about here, it will make more sense as you go through the lessons.

Seed Density Calculators

I mentioned Seed Density Calculators in the video. The calculators will tell you how much seed I recommend using on any size tray. Even circular trays.

Again, you will learn more about seed density in a future lesson. But if you want check out the Seed Density Course you can click below.