jamesiee
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Weak lettuce

I started germinating seeds a few weeks ago and I have transferred the seeds to a container and it was okay, but they are turning weaker each day. The leaves are rather small but the stems are very stretched out and weak and they can barely hold them selves up.

The seeds are in rockwool and (today)I have added more clay pebbles, so that the rockwool is not exposed to sunlight.

It seems that they are not dead (yet), but if it continues like this I am sure they will soon.

Does anyone know what is causing it?
Last edited by jamesiee on Tue Jul 05, 2016 5:27 pm, edited 1 time in total.

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rainbowgardener
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Re: Weak lettuce

They look like not nearly enough light and probably not enough nutrients. You put this post in container gardens not hydroponics. Why are you growing them in pebbles instead of soil?
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AnnaIkona
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Re: Weak lettuce

Why did you add the clay pebbles? Lettuce seeds germinate and grow quite well without them. It almost looks like the pebbles are keeping the seedling down, and bending them over.

Normally, spindly stems of seedlings means that they are not getting enough light. I think this is your case. Where are they placed right now? I would recommend a sunny, warm windowsill. Sometimes people even use grow lights.

Place them in a sunnier place and they should do better :)
Zone 8b, Canada

jamesiee
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Re: Weak lettuce

Rainbowgardener thank you for your message and advice.

I am sorry that I have placed this post in the wrong directory.

I will follow your advice and place them somewhere else so that they will get more sunlight, I think that might be the problem. As for the nutrient I added exactly the necessary amount that was written on the package of the nutrient product.

Pebbles keep the moist for the plants as I am very interested to use hydroponics to grow my vegetables.

jamesiee
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Re: Weak lettuce

AnnaIkona thank you for your message and advice.

I have added the pebbles as I am using the kratky method to grow them and (I hope) that they give more stability to the lettuce.

Now I placed them outside so that they receive more sunlight, I hope it will help and I will give an update if they are getting better!

Thank you both!

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rainbowgardener
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Re: Weak lettuce

We have a whole hydroponics section here: http://www.helpfulgardener.com/forum/viewforum.php?f=42

People there will be better able to answer your questions about nutrients,etc. All that hydro stuff reads like Greek to me.

I know there are standing water versions, but most hydro is done with flowing/ circulating water.

Hydro (and regular container growing) is usually done either outdoors or under lights. I don't do hydro, but I do start tons of plants from seeds indoors under lights. I never have had any luck trying windowsill gardening, especially not with seedlings. Here's a picture of hydro lettuce under lights. Note how close the lights are:

Image

It doesn't need to be any fancy kind of grow light. Regular fluorescent tubes work just fine.

So just out of curiosity, why do you want to grow your lettuce hydroponically instead of just in soil, in containers? To me the containers seem so much simpler/ easier.
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imafan26
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Re: Weak lettuce

The UH developed the Kratky method of non circulating hydroponic culture. Below are links to the method.
Lettuce seedlings are usually grown in a 1020 plug tray. At the farm we used oasis cubes or Sunshine #4 mix. The seedlings were transferred to net pots and the net pots were placed in a raceway with styrofoam sheets that had holes drilled in them that the 2 inch net pots could fit into. The sheets are about an inch thick so that only the bottoms of the net cups are in the water. at least 1/3 of the seedlng should be above water to make air roots. Hydroponic nutrient solution is added to the container. Usually it will be enough for the 45 day crop. The other method is to use a pop bottle. The lettuce seedling is placed in the top of a pop bottle filled with solution so that the roots touch the solution. The solution will evaporate but the roots will also grow into the bottle. As long as there is contact with the solution, it does not need to be refilled. Mosquitoes can be a problem so this method is not recommended outside of a netted structure.
http://www.hydroponics-simplified.com/raft-lettuce.html
http://foodrising.org/PDF/Three-Non-Cir ... ettuce.pdf
http://www.greenhousemegastore.com/product/net-pots/s
http://www.greenhousemegastore.com/prod ... grow-media
http://www.ctahr.hawaii.edu/oc/freepubs/pdf/vc-1.pdf
Happy gardening in Hawaii. Gardens are where people grow.

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applestar
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Re: Weak lettuce

This discussion has been moved to the Hydroponics Forum.

Any time a thread needs to be moved, the OP could just PM one of the moderators or simply mention it in the discussion if a moderator is participating. :wink:
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jamesiee
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Re: Weak lettuce

Rainbowgardener and Imafan26 thank you for the explanation and advice!

I went to UrbanFarmers (https://urbanfarmers.com/intro/) and it was a great experience to see Aquaponics, I don`t have the space or money to start a aquaponics system. So I decided to start with hydroponics and hope to have an effective hydroponic system in the future.

I am now a beginner trying (as cheap as possible) to grow lettuce using hydroponics and once I get the hang of it and gain experience, I will go a step further and further to have a nice hydroponic system in the house (in the future with growing lights).

I will check the links that you gave me Imafan26 thank you very much!

Applestar, thank you for moving the thread and I will make sure it will not happen again.

imafan26
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Re: Weak lettuce

Start up costs can be a lot for a system with a pump. But that is the beauty of Kratky. No pumps are involved. You still need the nutrient solution and it is best to start with a short crop like lettuce.
Happy gardening in Hawaii. Gardens are where people grow.

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