hydroponic Kratky non-circulating outdoor hydroponics, fill-and-forget 2015

[deep_roots]

After developing an interest in non-circulating, SNAP, and simplified hydroponics, I had opportunity to correspond with Professor B.A. Kratky of the University of Hawaii.  He provided links to his research on hydroponics, including the use of fill-and-forget hydroponics.  I had opportunity to test this fill-and-forget method with a Bhut Jolokia 'ghost' pepper.
 
Below is an overwintered Bhut Jolokia 'ghost' pepper that I bought from an area garden nursery center.

 
I rinsed the dirt off the roots and repotted into a bucket lid net pot.  A hole was cut with a utility knife through the lid of a 20-gallon trash can, into which the net pot was inserted.  The roots were surrounded with an inert media provided stability to the plant.  The 20-gallon trash can was filled with water until the bottom of the roots were covered with about 0.25" of water, just barely touching the water.  Dyna Gro Grow 7-9-5 hydroponic fertilizer was added at 1 teaspoon per gallon, along with some Epsom salt at one teaspoon for every 5 gallons of water.  The mixture was stirred.  As the plant grew, the roots began growing as seen below. The root length stay at the nutrient level in balance as the nutrient drops and roots grow longer.

 

 
Below you can see the root mass has increased greatly.
 
 
The Bhut Jolokia 'ghost' pepper has correspondingly grown huge and is loaded with peppers.

 

 
By the time the nutrient is used up, an entire harvest of peppers will have been completed.  The plant can be cloned or discarded, and the trash can and net pot rinsed off with a garden hose until next season.
 
https://www.youtube.com/watch?v=6LTq3WKxYV0

 

[Jeff H]

Interesting. I wouldn't have thought that long season plants like the ghost pepper would have responded so well without getting rotten roots after a while.

 

[Weed]

i read through a few times and maybe I still missed it but how long has it been in that container?

 

[deep_roots]

Interesting. I wouldn't have thought that long season plants like the ghost pepper would have responded so well without getting rotten roots after a while.

Jeff, the roots only grow and inch or two into the nutrient.  There is enough gas exchange at the surface level that no root root happens.

i read through a few times and maybe I still missed it but how long has it been in that container?

Heckle, what is pictured is a transplant that has been in this system around 3.5 months.  I planted late this year due to late May frost/freeze.  If starting earlier around end of April through September, a larger container would be used.

 

[pecker88]

I too am interested in Kratky hydro. and would like to start lettuce.
My question is how big does the plant have to be before the roots are placed "0.25 inches" into the nutrient solution?
Looks like yours was fully mature.
 
For my 10 gallon tote, I have 4 net cups inserted in the top but the lettuce (in rockwool cubes) is only 0.5 inches tall; tiny seedlings.
If I let the lettuce roots in the nutrient solution they will rot. Why, because 4 tiny seedling plants would never be able to drink at a rate to effectively lower the nutrient level, there by exposing more roots to air.
 
Make sense??

 

[deep_roots]

I too am interested in Kratky hydro. and would like to start lettuce.
My question is how big does the plant have to be before the roots are placed "0.25 inches" into the nutrient solution?
Looks like yours was fully mature.
 
For my 10 gallon tote, I have 4 net cups inserted in the top but the lettuce (in rockwool cubes) is only 0.5 inches tall; tiny seedlings.
If I let the lettuce roots in the nutrient solution they will rot. Why, because 4 tiny seedling plants would never be able to drink at a rate to effectively lower the nutrient level, there by exposing more roots to air.
 
Make sense??

For lettuce, you can either wait until you see roots emerge at the bottom of your rockwool, or let the nutrient touch the bottom of the rockwool.  Lettuce grows quickly.  Also, you can easily do 8 net cups of leaf lettuce with one filling of a 10-gallon tote.  Did you see the YouTube video with Professor Kratky?

 

[pecker88]

For lettuce, you can either wait until you see roots emerge at the bottom of your rockwool, or let the nutrient touch the bottom of the rockwool.  Lettuce grows quickly.  Also, you can easily do 8 net cups of leaf lettuce with one filling of a 10-gallon tote.  Did you see the YouTube video with Professor Kratky?

 
I just watched the video; very cool.
 
I started the lettuce seeds in rockwool and for the last 2 weeks had the rockwool cube sitting in the net cup on top of a rock. The rock held the rockwool cube above the nutrient solution level; I didn't want to swamp the new seedlings. There are 1/4" roots coming out of the rockwool so last night I removed the rock and put the cube into the bottom of net cup.
 
I'm going to add 2 more net cups to my tote lid; 3 on each side. I think 4 on each side would crowd the lettuce heads.

 

[CelticFarmer]

Be pretty cool to see how a dwc bubble bucket would do side by side with your no circulating setup. Dwc is definitely a lot of maintenance compared to the Kratky, but those are some nice roots. How did the peppers taste? How was the heat level?

 

[Hawaiianero]

I saw this trick with a cucumber plant and it worked very well since cucumbers die off after a few months. I never though to try it with a pepper plant.

 

[deep_roots]

Interesting. I wouldn't have thought that long season plants like the ghost pepper would have responded so well without getting rotten roots after a while.

Roots only grow into the upper couple inches of nutrient and do not rot since that surface of water has enough oxygen in it.

Be pretty cool to see how a dwc bubble bucket would do side by side with your no circulating setup. Dwc is definitely a lot of maintenance compared to the Kratky, but those are some nice roots. How did the peppers taste? How was the heat level?

I got 94 ghost peppers off this plant, with searing heat and great flavor.  DWC is more productive, but this method was SIMPLE.  Set it and forget it.

I saw this trick with a cucumber plant and it worked very well since cucumbers die off after a few months. I never though to try it with a pepper plant.

Based this pepper grow off the cucumber plant experiment.  Given enough nutrient, the pepper is sustained over a longer period of time.

 

[Hawaiianero]

Curiouser and curiouser.......
 
I wonder how it would work if you inverted the lid (dome shaped) so that it would funnel down any rain water and maybe prolong the grow?
I don't know much about hydroponics but my simple mind seems to think it would work.

 

[deep_roots]

Curiouser and curiouser.......
 
I wonder how it would work if you inverted the lid (dome shaped) so that it would funnel down any rain water and maybe prolong the grow?
I don't know much about hydroponics but my simple mind seems to think it would work.

Good question, but would not work.  Once roots become prolonged air exposed, they commit to gas exchange and not nutrient uptake.  To resubmerge those roots would essentially drown them.

 

[resili626]

Good question, but would not work.  Once roots become prolonged air exposed, they commit to gas exchange and not nutrient uptake.  To resubmerge those roots would essentially drown them.

 
 
Hey, can you clarify what you mean by prolonged exposure to air will commit the roots to gaseous exchange and not nutrient uptake? If I understand you correctly, you're saying that if the roots is exposed to open air, then you can't use the kratky hydroponic method anymore?  

 

[deep_roots]

 
 
Hey, can you clarify what you mean by prolonged exposure to air will commit the roots to gaseous exchange and not nutrient uptake? If I understand you correctly, you're saying that if the roots is exposed to open air, then you can't use the kratky hydroponic method anymore?  

The lower couple inches of roots continues to grow, staying in contact with the nutrients. 
The roots that have been exposed to the air, after the nutrient level drops become solely gas exchange roots.
These air roots can no longer function as nutrient / water gathering roots.
So refilling the container will cause plant injury.

Professor Kratky describes this growing method as the following: 
 
"When the nutrient solution level in the tank drops below the containers, new
roots will have emerged from the containers. The lower portion of these roots is
immersed in nutrient solution while the upper portion resides in the moist air layer
between the cover and the nutrient solution. Raising the nutrient solution level by
rainfall or additions above 2 cm after this point may cause plant injury. Plant
growth continues until less than 10 percent of the original nutrient solution remains
when the crop is terminated and a new crop is initiated."
 

 

[resili626]

The lower couple inches of roots continues to grow, staying in contact with the nutrients. 
The roots that have been exposed to the air, after the nutrient level drops become solely gas exchange roots.
These air roots can no longer function as nutrient / water gathering roots.
So refilling the container will cause plant injury.

Professor Kratky describes this growing method as the following: 
 
"When the nutrient solution level in the tank drops below the containers, new
roots will have emerged from the containers. The lower portion of these roots is
immersed in nutrient solution while the upper portion resides in the moist air layer
between the cover and the nutrient solution. Raising the nutrient solution level by
rainfall or additions above 2 cm after this point may cause plant injury. Plant
growth continues until less than 10 percent of the original nutrient solution remains
when the crop is terminated and a new crop is initiated."
 

 
Ah. Can I then slightly modify the containers whereby there's a reservoir of water that will keep feeding the container with the same level of water when it is depleted so that the lower portion of the roots will continue to grow whilst being submerged in the nutrient solution while the space available for the upper portion of the root remained constant? Additionally, can I choose to NOT terminate the crop but then plant the pepper into a soil-based planting medium once the nutrient/liquid level is sufficiently depleted? 

 

[cubbieblue82]

Planning to do a few Rubbermaid things this way this year. Wondering the same as resili626

 

[deep_roots]

 
Ah. Can I then slightly modify the containers whereby there's a reservoir of water that will keep feeding the container with the same level of water when it is depleted so that the lower portion of the roots will continue to grow whilst being submerged in the nutrient solution while the space available for the upper portion of the root remained constant? Additionally, can I choose to NOT terminate the crop but then plant the pepper into a soil-based planting medium once the nutrient/liquid level is sufficiently depleted? 

If you want to start out in Kratky and then move plants to soil, watch this video on Ginger production and take the idea of the float-valve feed and soil pots to use with your peppers.
https://www.youtube.com/watch?v=x0UKBKPx8gg

 

[resili626]

You sir, are the man. Thanks!

 

[Malarky]

So is overwintering possible after a season of "kratky in a can"? I hope someone with more time tries and reports back. 
Probably should just clone and start over?
 
I wonder how much energy is diverted from vegetative/fruiting growth to that massive root grow, that would otherwise grow a bigger plant/more pods?

 

[cubbieblue82]

is it feasible to do this with a homemade mix of masterblend, CaNO3 and MgSO4?