Grow Lights or Not?

[joe645]

I recently started some lettuce (seed) in a grow dome tray with a RGB grow light on 16 hours and off 8. Small plants emerged but after 4 or 6 weeks, the media (rockwool) started to turn green with alge. Reading about alge, many experts say this is caused by light among other things and to reduce the possibility of this, I should remove the light source. Isn't that counter productive? Don't the seedling need grow lights to bloom?

[Shawn]

I would surely think they need light.  Is the rock wool covered?  Light is hitting that it appears.  AG uses the pod covers, which are really essy to make if needed to help keep the light out.   It still can cause the algae but helps to keep it down.

In the past I have carefully dipped a qtip it a peroxide and tapped the area where needed without touching plants.  Sometimes successful and others times I have started over.

Let's see what others say on this topic. 

Unless they are in a sunny spot near a window, they need light to grow. I have found in the past that rockwool does not drain well, and also, the light grey  colored surface encourages algae. I have not had many successful projects using it (some like using it). If that is the only medium you have and really want to stick with it, I would suggest surrounding the cube in clay balls for better drainage, and somehow covering the top of each cube with cardboard or something to block the light. Algae is harmless, BUT it can get slimy at times..not desirable with edibles.

I use the sponges for my media in the Hydrofarm box . I use the humongous size sponge and algae has no desire to grow there(at least if it does, it is not visible and there is no slimy indication), even though openly exposed to direct light bulbs.  They are from Parkseed and are suggested for use with the Bio Domes .

parkseed.com/bio-dome-refill-sponges/p/v1597/

You can get an idea from viewing my link of my projects here:

aerogardenaddicts.com/thread/1660/winter-lettuce-salad-box

I hope your lettuce does well. Photos will also help members trouble shoot your problem. Fingers crossed!

[joe645]

Thank for the tips. I was in error saying the media was rockwool when in fact it was the sponges in my Bio Dome tray. One outside tip was to cover the sponges with reflective mylar and poking holes to grow. Then as the plant grows it will have both direct and reflected light. I may try that next round.

Is it green algae or white mold?

[joe645]

It was green. I discarded the few plants that I had started because they didn't look well. For now, I am going to stick with my Aero Garden Harvest to start my seedlings. I am learning quite a bit about what I need to grow healthy fruits and veggis. My tomato farm is looking like a jungle (Big Boy Tomatoes). I started them without realizing just how big they grow upward and outward. Mike (The Pepper King) has helped me a lot with construction of support fences since I cannot just string support from the ceiling due to my grow light source. Here are a couple of pic. My tomato farm in the first and lettuce in the second
i.vgy.me/H5uWD5.jpg
i.vgy.me/gq9hOo.jpg

Ah! Now I have a totally different picture of it..I thought you were starting your seedlings in the Harvest to plant them later in the Bounty! But you are starting them to put them in the dwc tubs

[joe645]

That's right. I start them in either a Aero Harvest or a Bio-Dome and once they fully root, I transfer them to my totes. The totes have manifolds that spray water into the net cups every 2 hours. The totes have drains to change the water and float valves so the water level stays constant.

[joe645]

One of my ButterCrunch Lettuce plants has taken on an unusual shape after first harvest. Doesn't look like others.

[Shawn]

Looks like a large tree in the forest.