A Whole Lotta Time (since the last update)

A project log for The Little Green Tower

A mist-based tower system for growing leafy green vegetables

Chris JohnsonChris Johnson 01/03/2019 at 20:072 Comments

We've had many tasty salads over the holidays!  Below are the remains of the last two plants from the current test crop, which I pulled about 10 weeks after sowing.   The leaves from the last picking are in the second photo.

The plant photo shows how the roots took on the shape of the bottom of the pod, as they spiraled around the surface.  Any roots that grew through vertical tubes between pods were occasionally pruned.  The roots got a bit damaged when the other two plants in the pods were removed early, due to their bolting.  The lesson is to make sure to match the lifecycle of the plants in one pod.

I'm still getting some leaf tip burn and have not determined why.  Truthfully, I have been working more on system design than nutrient optimization, so I'm fairly sure that it can be corrected.

As shown below, I'm working on building a second test cell for A/B testing of nutrient levels.  The second system will of course be "New and Improved!".  The biggest update is a simpler control valve design that costs less to make and should also be more reliable.  I've also made some small modifications to be control board design and will be having new PCBs made soon.  I will be documenting the new system in project logs as I build it.

Finally, if you've made it this far, please consider posting a question or comment.  Interacting with potential future users will help me tailor the final design.


Chris Johnson wrote 12/17/2019 at 01:37 point

Ryan,Thanks for the comment and for the tip on the tip burn :-).  I don't think it's a ventilation issue, since the enclosure is actually fairly open.  I did some research on the particular lettuce that I was using and found that it was more susceptible to tip burn than some others.  I've also read that the faster the lettuce grows, the more likely it will get tip burn.

  Are you sure? yes | no

ryanhamamura wrote 12/13/2019 at 18:37 point

Hey Chris, I just read through everything on this project; it's awesome man. Keep posting! Your tip burn might be a ventilation issue; have you tried setting up a fan pointed up at the plants? 

  Are you sure? yes | no