Sunday, March 13, 2011

Lettuce and DWC Update 13 March, 2011

Time for an update to the current lettuce grow in both the 1st and 2nd DWC systems.  Journal entries for the past few weeks have been pretty simple; "added a gallon of fresh water", "checked PH", "PH normal", "growth is solid", "roots are expanding well, etc.". 

Below are photos of both systems as of 13 March, 2011.  I will refer to the mature lettuce system as DWC 1, and the juveniles as DWC 2.

Below is DWC 2. The lettuce in this system is growing quite well and each group has more than three leaves.  All pots have roots extending at least six inches into the nutrients and are very healthy.  These varieties are part of Totally Tomatoes "Bon Vivant Mesclun Blend".  It is described as "a gourmet blend of exotic leaf lettuces of the best flavors, textures, and colors from reds to greens".  The seed packet identifies at least seven varieties in the mix and I attempted to germinate and then thin to the 7 varieties.  I attempted this by separating 7 different variants of seeds, but it was not easy or precise. I notice at least 5 different varieties as of now, but hopefully further growth will show the additional two as individual differences continue to appear.  There are 2 varieties per net pot in this system.

Below is DWC 1.  This has been in operation for several weeks and has produced heavily.  We have harvested nearly every other day and it rebounds quickly.  This system contains a couple net pots with 2 plants each.  Since it appeared manageable early on, I decided to proceed with the technique in the 2nd DWC system.  I believe that remains feasible.  It doesn't necessarily improve the quantity nor does it crowd, but it will allow 2 types of lettuces as I have done with DWC 2.  It was a good experiment and I will use the outcome when dealing with "mixes" of different un-separated varieties in a package.

The roots are denser than was shown in the February photo, and the center "baby" leaves are much tighter and faster growing.  Those are by far the best leaves for flavor.

I believe I have the timing in place to allow a smooth transition from systems without any delay in lettuce harvests.  The DWC method continues to prove itself as trouble free and highly effective in growing solid plants. 


  1. Shouldn't the roots be white?

  2. They are Rich (white), well off-white that is. The lighting makes them seem darker.

    I noticed they go from bright white to dull after the first nutrient change with each grow. I've asked the pros and they have all agreed that unless there is an odor, signs of rot (blackened ends), or decreased foliage, it is completely normal. The previous batches have done very assuming this may hold true this round.

    Any different experiences with this?

  3. Great Blog, when you harvest the lettuce do you start over or leave enough to continue growing?

  4. Thanks Thomas, your comments are very much appreciated. It has been a fun blog!

    On the harvesting...we trim the biggest bottom leaves and a few from the center (very sweet) each time.

    The bottom picture of this blog post was taken right after harvesting enough for 2 large salads. Enough of the leaves are left to insure they grow back rapidly. We continue that process until they finally turn bitter and then they are destroyed.

    With two systems running, we hope to avoid any "gaps".

    The "outside" lettuce will be planted in waves and each batch harvested all at once.

  5. Thanks for clarifying on the roots. They look pretty brown in the picture, but as you said, that can be from shadows and white balance.

    How often are you changing the nutrients? I'm setting up a DWC for lettuce right now and I'm on the fence about whether or not I want to change them every week or wait longer.

  6. Thanks Mister H, my veggies are still in their infancy stage atm but growing very fast and cannot wait till they are large enough to put in a aero/hydro system. I was not sure if I could trim them without killing them. So Mister H, I am not sure if you have tested this but, do you find a hydro or aero system works best for lettuce?

  7. Rich: I am at about the 20-30 day mark (in the system) for changing the nutrients from 1/2 strength to full strength and then I let them run until they turn bitter. That is not a hard and fast rule yet, but the result of some tweaking. I intended originally changing at 14 days, but lettuce is not as demanding on nutes as I had thought. 20-30 is fine.

    Thomas: Good luck with those little fellers! I started trimming at about 30 days and use your judgment on how much to cut. They grew back fuller and very quickly. I pulled the larger outer leaves and a small portion of the inner leaves and this has seemed to work well.

    I have not used an aero system, but I understand it is very efficient. This is especially true for larger flowering plants such as tomatoes and cucumbers.

    Best of success to you!

  8. What nurtient mix are you using my new found internet friend?

  9. CNS17 Grow. I like it so far and also use it on non-hydro houseplants. It seems to do very well and has been cost effective.