My roots stink!

[Tim]

Hi guys, I have raft system using the standard styrofoam sheet and little plastic planters shoved into inch and half holes. The plastic planters have small river pebbles in them as media holding the plant sturdy. I have lettuce, kale, and cabbage i his table to see what is going to grow at what rate. Some of my plants have long beautiful white roots and some have no showing roots. The ones with no new root growth smell like feces when you smell the bottom of the plant towards the root. The plant looks fine but it smells like the root is rotting. What to do?? Will the possibly rotting root kill the system??

[Jonathan Kadish NYC AA Chair]

You likely have anaerobic conditions in you raft. The area that stinks is not getting enough oxygen so you need to add aeration there.

[Jon Parr]

Yep, likely anaerobic raft water, though cold water and slow growth can show the same results while being quite aerobic. Roots catch shit, and if the water is too cold for rapid root growth and proper bacterial action, they will keep accumulating gunk until the area under the surface becomes anaerobic, and stinks. It can stunt or kill your plants, so best to fix the prob.

[Tim]

I went out there today and pulled out every plant. The parts that were obviously rotten I just pulled off (they had already detached from the plant so it was just a matter of pulling it out of the media) and discarded. All of the plants that were experiencing this also showed some minor but new root growth!! I think since I cleaned the rot root out it is going to thrive. I put these plants in the water a week before I got fish so maybe the root died from lack of nutrients?? I have an aerator in the fish tank now also. I will monitor and report any changes. Any other ideas from you guys so I totally avoid this from happening again?

[Jonathan Kadish NYC AA Chair]

Do you have any filtration of the water going from your fish tank to your raft grow bed? Failure to filter properly will result in solids building up on the roots and bottom of the raft tank.

[Tim]

I do. I had a very nice two stage swirl and filter box system but I could get the height right for a gravity feed. So, I just have a straight pipe gravity feeding the fish tank into the grow table. The water hits two filter pads before dumping into table. One is a thick coarse filter for big solids and one is for catching very small invisible waist. The roots that are long and white in the water have no build up on them at all.