Getting the darkest greens possible

[Joe Bifano]

I am growing micro-greens for a customer and the last few orders they wanted to know if I could get them darker green.

Usually you grow them to there first true set of leaves in just water. They say you do not need anything more than water because there is enough nutrients in the seed to get it to this stage without adding anything.

I am able to compare them to the competition right next to mine and they are a shade darker.

I have 2 systems setup and #1 has a PH of 6 or lower, Nitrates are at 0

#2 has a PH of 7.8, and nitrates are 0

Both give me the same results in a green color that is okay but not as dark as my competition. They say you do not have to give them any nutrients because they are harvested at such a early stage but yet theirs are clearly darker.

I can't really tell if there are any deficiencies because they do not grow that much to be able to tell.

I have been thinking about getting a Iron test kit and see what I am at in my 2 systems and if low add Iron to them.

I am also thinking about taking them out of the Aquaponic systems and putting them in a hydroponic setup with more Nitrogen.

If I don't get them darker I will not be able to sell to them. Everything else is the same.

Any one have any ideas?

[Joel Traas]

Just a guess,

I recently moved my indoor system outside.  Iam not growing microgreens, just lettuces.  But everything was much greener almost overnight without changing anything else.  Could it be the amount of light? 

[Joe Bifano]

I am in a greenhouse so I am outside. I can't grow them totally outside because of the animal's, cold nights and wind. I was growing a month or 2 ago inside and they are better but not very dark like I think they should be. 

I have 16 varieties growing and my collards are the darkest. If they could all be that way it would be great.

[Vlad Jovanovic]

Joe, It's hard to believe that micro greens could exhibit much in the way of nutrient deficiencies (not saying that it isn't possible, just that it's hard to imagine is all). 

Not all seedlings/sprouts/micro greens pop with the same colour tone, but if they're pale, it seems like the issue would be one of light. If you can't supplement with some good quality light for whatever reason maybe (and this is a big maybe seeing as how it's micro greens in question) you could amend with some N. Again, I'm not sure how that would play out in such a young crop, but a too deep, too dark, lush, overly rich green colour is normally one of the tell-tale signs of too much N. But I'm pretty sure micro greens should have most all of what they need contained within their cotyledons?

Of all the stuff I grow, it seems like my Tatsoi and Komatsuna come out of the gate greener than most others...don't know if throwing some of those into the mix, if you haven't already, would maybe help to spruce things up a bit...

At any rate good luck to you...

[Alex Veidel]

Sounds like lighting to me!

[Joe Bifano]

If it is light I can understand that. I am in Colorado and the competition is in Southern California. So because of the fact that I am up at an elevation of almost 7000 and In Colorado and they are in closer to the sun's equator they will have more light.

It is not that the Micro greens I am growing are not great tasting, healthy, locally grown and last as long as there's, they want them just as dark green or they will not buy them. They are saying that the darker, greener micro's from the competition are better because of it. I can't convince them otherwise. They want mine but they are saying they have to look the same. My price is better so as soon as I get this darker color I am in.

The competition is growing theirs via hydroponics so they could be using a more N or way more than I am getting from the Aquaponics system.

I have tried both Tatsoi and Komatsuna and I know it's not Komatsuna becasue of the leaf shape. I can't seam to get Tatsoi to germinate. I am using burlap and everything but beats, celery and cilantro have to be in another media, at least for me. It could be my seeds are no good but all of the other Asian seeds I get from the supplier are great.

I have about 11 things in my mix and some are great but the general overall cast is lighter than theirs. Even there stems are darker. I only get that in a few varieties.

I really can't add any lights where they are in the greenhouse.

Besides going to hydroponics and using a mix that has more N what could I do to add more N to my setup without missing up my fish. I can spray the leaves with a little Fish water mixed with N or Worm castings.

What would you use?

[George]

addition of aged urine will bump up N.  You might try EDDHa iron once per week to see what effect it has.

[Vlad Jovanovic]

I think that Joe in his situation needs something a bit more 'refined'. Look for a source of N that won't tax your bio-filter. (Unless you've got bio-filtration capacity to spare) ...

Saltpetre or nitre might do you good. It's basically unrefined potassium nitrate (so it still has 'impurities' comprised of calcium nitrate...which isn't a bad thing in an agricultural scenario)...and should be immediately plant bio-available...

Making saltpetre or nitre yourself is probably out of the question for you, since it takes about the better part of a year.

You might try growing the greens out with the KNO3 additions separately in a small trial set up first, and see if that gives you the deep green colour your after...Don't over do it.

George said:

addition of aged urine will bump up N.  You might try EDDHa iron once per week to see what effect it has.

[Sam Burton]

I'm wondering if something as simple as a capful of maxicrop might do the trick.  I had a young system that I planted squash in before it was mature enough. The leaves actually had become almost pastel. I added a capful of maxicrop and within 24 hours they were improved.  It's two weeks now and you can't tell they were ever sick.  Of course, I've never grown microgreens so I'm really not much help. 

[Jon Parr]

Joe, I agree with Vlad, micro-greens are not likely to be deficient in anything, and are commonly grown in tap water (depending on how 'micro' you are harvesting them).

I'd bet me left nut (already lost the right one...) that you need UV light to darken them up. Most greenhouse film plastics, and all polycarbonate panels are UV resistant, so greenhouse produce is always pale compared to outdoor crops. You can get UV t-5 lights, leds, or my personal favorite is the Phillips 400 CMH bulb, made to fire in a standard HPS magnetic ballast, which puts out brilliant white light with plenty of UV. Great plant color with this CMH bulb.

You don't need to rely on artificial light for growth, just for UV stimulation of anthocyanins (red, purple and blue pigments that act as sunblock to leaves). For instance, a purple lettuce will grow purely green in a greenhouse, and the exact same seeds grown outdoors will look like Barney after 2 weeks in Hawaii. 

I copied this from google:

"Lettuce and other red leaves have anthocyanins that are not part of the photosynthetic pigments. The anthocyanins are antioxidant and provide protection to the plant. Anthocyanins are what color fruit, flowers and leaves with magenta, purple, red or blue. Recent literature reports some 550 plant anthocyanins for protection from UV or oxidative damage."

[George]

Interesting, Jon and it makes me wonder if there are other options for greenhouse plastics, materials which allow UV entry.

[Joe Bifano]

I harvest at the first true leaf or just before on some varieties. I started out with just tap water and they looked great to me.  That was all I did because that was all they needed. I am not doing it because they need it but because of what they are saying to me.

I then adapted a couple of things in the aquaponic system to auto water them and they got a little greener, probably becasue of the nitrogen and iron in my system, but they complained all the time about their light color.

My red kale, purple kohlrabi, purple radish and red cabbage has great looking red and purple stems. Also I have lettuce in the same system like red romaine, red salad, and other red lettuce and they are dark red. My green lettuce is pretty good and all in all. When I sell it I have never had a complaint from individuals on the color just my broker.

Jon, on the lights like the Phillips bulb, I have 2 areas about 4' x 28' that holds 100 1020 trays. How many light fixtures would I need?  What would one bulb cover?

Right now I harvest 50 trays a week and I will be going to 200 per week if I can get the color. If it takes a lot of bulbs I would think that Vlads idea on the saltpeter would be a lot cheaper to get the darker greens they want.

I think what I am seeing is this other company is enhancing their product to get the darker colors via higher nitrogen. I am pretty sure they are growing hydroponically and I am growing aquaponically. If they use a high nitrogen nutrient I may never get the colors they have without switching to hydroponic growing or adding the saltpeter as Vlad suggested.

No matter how I educate my partner/broker on my natural growing technical abilities they have to deal with their wholesalers that think the darker greens are better. It's not that I am not growing them correctly and getting a great product it's their thinking that darker is better.

I have also seen a video on the competitors greenhouses and they have several acres of greenhouses just for micro-greens. They had several 30x96 greenhouses with no lighting growing in 1020 trays.

[Vlad Jovanovic]

The glazing on my GH seems to be a NON-borosilicate glass...(some type of fused quartz-type I believe) so plants have no problem whatsoever producing nice deep rich anthocyanin tones... 

Hey Joe... (god I love saying that) remember back when your tomato seedlings were turning purple and I wrote you that (probably long winded) explanation of why...(when plants are deficient in P...intra-cellular energy exchanges are stymied, so sugars tend to build up, go un-used and hence anthocyanins form... and that's what gives them that purple colour...letting you know they are deficient in P)...Maybe you can use that to your advantage somehow? Less P and more N should darken things up in theory...(keep in mind these are 'surrogate' solutions, the real deal would be to get more (of the proper) light to the micro greens)...