MicroGreens - Germination Experiments

David Trammel's picture

One of the secrets of success with growing Micro Greens, seems to me to be, identifying those plants that germinate quickly and grow large enough to harvest in a short period of time.

A plant that takes 5-10 days to germinate is better than one which takes 7-12.

As an experiment then, I have seeded 12 different plants into two of my seed flats (6 per each) as a way to see which plants grow quicker. Since watering and soil will be a common factor, early germinaters should germinate "early".


As a reminder, I am using a two flat system.

The larger flat on the left is a commercially available, purchased at a local organic grow store. It comes with a clear lid and retails at about $8. The slightly smaller flat on the right is one I got for free at my local nursery in the Spring. It typically holds six, 6 cell plastic starters. It has holes in the bottom, which allows excess water to drain out, but in this case it allows me to water from below.

Here is the two flats with soil.

You will notice that the plastic dividers in the smaller flat, allow a natural division of the soil. In this experiment, I have made 16 holes in each sub-division, approximately 1 inch apart.

Here is a list of the plants I am using.

1st Flat:

Bok Choy Tatsoi, Spinach (Bloomsdale Long Standing), Kale (from my garden), Collards (Yates), Mustard Greens, India (Florida Broad Leaf), Lettuce, Romaine (Paris Island Cos).

2nd Flat:

Kale, Dwarf Siberian, Spinach, Baby's Leaf (a hybrid), Black Mustard, Herb Dandelion, Lettuce, Romaine (from my garden), Amaranth, Green Calaloo.

Why these? I had the seeds, lol.

Honestly I am bad about buying exotic seeds with the intention of planting them but never do, so this gives me a chance to see what some none standard plants will do. Any plant whose leaves are eatable will have micro greens that are eatable. Two plants, I actually harvested seeds from the ones I grew this year.

I found the easiest way to plant these, was to use the end of an old toothbrush to make the holes, and a wooden shiskabob stick to select the seeds. A small clear plastic cup is also helpful, as a place to pour some of the seeds from the paper envelope.

I would wet the end of the shiskabob stick with my tongue and dip it into the seeds in the cup. Depending on the size, 4-6 would usually stick. You can then transfer them to the predug hole in the flat and flick them off with your finger.

All seeds but the spinach, were seeded with 3-5 seeds per hole. The spinach seeds were much larger, and I only used 2 per hole (seeding with my fingers).

Once each flat was seeded, I used a squirt bottle to liberally wet the top of the soil, then once I placed them in the front room under the grow lamps, I added about an inch of water to the lower flat. It should wick up and wet the solid from below. The clear plastic tops were then put on them.

I will report as they progress.

David Trammel's picture

Here's another article from Mother Earth News


This guy even uses sunflowers for greens

Blueberry's picture

Nice to have something to go with the greens yes, I have tribe members who like to do this it can be very tasty https://www.youtube.com/watch?v=e-YKDPJ0Iu0

ClareBroommaker's picture

I also suggest that you move some of your experiments outdoors. Most greens can be harvested from repeatedly when grown in the soil, as you did from your bucket-grown vegetables. In St Louis we have a warm autumn, so there is a lot of time for greens to keep growing even after the autmumn equinox. After that you can use light penetrating covers over leafy greens to keep them growing. Most of those would be petroleum products, but right now there are scads of scrap fibers and plastics you can use. For example, years ago, I put a plastic cover that had wrapped a sofa over a bed of Red Sails, Oak Leaf, and Bib lettuce. Old windows might work, too.

And since you are using "piped in" energy anyway, you could also do what I did back then: stick a light bulb under the plastic. At the time I used a single incandescent bulb, usually just during the dark hours. Again, it was a cheapo Lights of America work light with an aluminum bowl-shaped reflector. I used it not as a source of light, but of heat. My lettuce stayed useable in that set up through a couple of light snows. It was sometime in January that I had to give up. It was amusing to look out and see a glowing white blob in the garden as the plastic covered in snow acted as a light diffuser....Natural heat sources to use outdoors include hot compost or fresh manure.

Our USDA average minimum temperature in winter has gone up since I did that. So generally I would expect I could a little longer keep harvesting leaf lettuce from under a cover without the lightbulb heat.

Blueberry's picture

Did you make your own mix or use one from a garden center? Since it has been 8 days from your post the plants should be 1/2 to 1 inch in high. We try for what is call baby green 21 days from planting to 45 days full size on most plants. Looking forward to a update

David Trammel's picture

Did you make your own mix or use one from a garden center?

I used Jiffy's "Natural & Organic Seed Starting Mix". 12 quarts is $5.49. I estimate I can fill 5-6 flats, so about a dollar a flat for soil. I'll do a cost breakdown when I get a chance.

Since it has been 8 days from your post the plants should be 1/2 to 1 inch in high. We try for what is call baby green 21 days from planting to 45 days full size on most plants. Looking forward to a update.

Ok its now ten days in and here's pictures of the flats. They are actually doing better than you would expect.

I took the plastic covers off about 3 days ago, right after you posted. Notice that the back area of the first flat has dried out some. There definitely seems to be a correlation between wet soil and whether there are plants in it. Perhaps the roots draw up more water than they take in?

Also the grow lamps are set at about 24" from the flats. I don't know if that contributes to the long thin stalks on the seedlings. Maybe if I lowered the lights?

As you can see the seedlings are 3-4 inches tall.

In first flat on the right seems that the India Mustard sprouted quickly, with the Collards somewhat sprouting, about half of the holes have sprouts.

In the second flat, I had a lot more success. The Dwarf Siberian Kale and the Black Mustard (top left two) came in well, with the Romaine Lettuce (left bottom) and the Amaranth (right bottom) both sprouting.

Here's a better picture of that flat.

Still not the best unfortunately. The green plants tend to hide on the brown dirt background.


I am looking for some suggestions as how to proceed.

One, I can leave these flats to grow a bit and see what happens. I expect that the seeds that have sprouted will develop like the original flat. Now I've seen all but the Amaranth grow already. Removing the plastic covers means that the plants that haven't germinated so far, won't have a high humidity environment to sprout, like the early ones did. That will effect how they sprout.

Two, I can either remove and replant the plants that have sprouted, into 2 gallon containers, and let them grow. Means I'll have plants to harvest in a month and a half. I'm not really hurting for food though. I am inclined to cut all of the early sprouting plants off, and then recover the flats to see if the late sprouters do sprout.

Opinions or suggestions are welcome.

Sweet Tatorman's picture

Perhaps of some interest is my observation that there is considerable variation in growth rate among the varieties of Kale. I planted my Fall Kale about 4 weeks ago [Aug 22] and used two varieties; Dwarf Blue Scotch and Dwarf Blue Curled. At 4 weeks the Dwarf Blue Scotch are about 3 times the size of the Dwarf Blue Curled. It may take considerable experimentation to find the variety that is best performing for your microgreen purposes.

David Trammel's picture

I suspect you are right. The one good thing is I have alot of space and time available and plenty of flats to try a variety of seeds.

To me, micro greens are kind of the "first baby step" for beginning Green Wizards to learn how to grow food, which I consider one of the prime skills all Green Wizards should know how to do. I hope to be able to develop a small indoor set up, perhaps on the size of a large bookcase, that is a year round system of growing micro greens.

I'm on the fence as to whether flats or 2 gallon containers will work better, and I do think some sort of indoor lighting is a must, for Winter. Figuring out which plants germinate fast is going to be high on the list too, though end output will be important as well. If a plant takes a few days more to germinate BUT really grows alot of leaves, then that would be something to know.

After I get the micro greens rotation worked out, then the next step will be an indoor worm farm set up, so that organic waste from the kitchen (and the containers) can be recycled into compost for the soil of the containers. That should be an interesting experiment, I've never touched worm farms before so it will be a big learning experiment for me too.

ClareBroommaker's picture

They look extremely pale and drawn out due to a lack of light. Next time I suggest you put the lights WAY closer to the soil surface. I sometimes rest my light fixture (the frame, not the bulbs) right on the edges of the seed trays., then as the seedlings grow, I back the lights off to be just barely above them. It is not unusual for me to let my tomato and pepper seedling leaves actually touch the 40 fluourescent bulbs.

I have my light fixtures suspended by chains from the ceiling. To raise them gradually, I just lift them up one link at a time. My chains dangle from hooks in the ceiling, and there are holes in the top of the fixture to attach the chains with S-hooks. I think the fixtures, which came with the bulbs & chains, are the cheapest, crappiest shop lights you ever will see. They cost me $6 each 25 years ago. Lights of America brand and terrible to work with, but they get the job done in January-Feb-March-April when I start seeds in the cold house. My seedling do grow thin leaves lacking substance, and I can't wait to get them out to some real sun; my lights would not produce lush foliage for eating.

Personally, I would snip those off now and consider them sprouts for immediate eating.