An Outdoor, Nearly Rainproof, Kratky Tote System with Low Maintenance

 

Kratky is a good method for outdoor growing. Because it needs no power, it can be positioned anywhere where it gets sufficient light. Vining squash and melons can trail out on a patio, rather than in the grass. One problem of growing in outdoor containers is heavy rain diluting nutrient. I began growing tomatoes and peppers in Sterlite 40-gallon totes, one or two plants to the tote. But the lids of these and many totes are recessed. Most of the area of the lid is below the raised rim, so the whole lid becomes a rain catchment, and if net cups are just set in 2” holes in the lid, the rain drains into the nutrient.

 

To prevent that, I designed these with risers that support the net cups above the lid’s rainwater level. I use 2-3/8” grommets. The interior of those grommets fit the outer diameter of 2” Schedule 40 PVC pipe. A short stub of pipe fits snuggly in the grommet.

Most of this report will deal with construction problems, because there are some that I had to deal with, but hopefully, you can avoid most of them.

First, the grommets specify a 2-7/8” drilled home. That is a hole drill size not commonly found in the inexpensive hole saw sets. I bought one on Amazon with mandrel for $14. But the groove around the grommet that grips the wall it passes through is fairly deep, and I found that I could make a 3” hole that would seal just as well, and all common inexpensive hole drill sets have that size, and such a set is very useful and indeed necessary for DIY hydroponics.

 

 

In the grommets I had, that groove is very narrow, 1/16”. The lids of most totes are significantly thicker than that, and it would be difficult to fit the grommet. I found that if I used a rotary tool to bevel the edge of the hole, it helped me get the groove to start slipping over the edge of the hole. Once I was doing that, construction was much easier. Trying to fit the grommets without making that modifications was incredibly frustrating.

I have since found that the grommets are also available with a 1/8” groove, which is likely to fit far more easily. They are more expensive. $5 apiece, rather than $3. Both are on Amazon.

Grommets in the 1/8” groove version.

 

I also learned to use the tool to bevel the outer edge of one end of the short piece of pipe so it could more easily begin to slip through the grommet. Totes got three risers installed. My initial intent was to use the two outer ones for plants and the one near the middle front as an inspection and service port. But I went ahead and used all three for plants on some totes.

It only takes about 2” of pipe for enough to extend above the rain line. I happened to have some 2” black PVC tube, which is why my pipe stubs are not white.

This obviously limits to 2” net dups. But I use 2” net cups for everything and find no problems with larger plants like peppers and tomatoes. So, the Kratky tote’s only rain exposure is the very minor one of what rain could make it through the foliage to run through the medium in the net cups. Rain falling anywhere else will simply accumulate in the recessed lid, prevented from getting inside by the grommets and risers, and can be easily dumped by tilting the lid to prevent mosquito breeding.

Note that the risers will prevent a new seedling that has not had roots descend from reaching the nutrient at first. One way to address this is to insert a cloth wick into the net cup. You can also slide the riser down into the grommet so that the net cup medium can reach nutrient in a full tote.

Instead, I grow my seedlings in a Kratky bucket with several holes in the lid until they send down sufficient roots. That also provides them some indoor protection from wind and sun. When they have sufficient roots, I lead the roots down through the risers. The nutrient starts high enough for them and is allowed to drop to one-third in the usual Kratky way. 

 

This is a finished tote.

 

 

Underside of the tote lid.

Newly started tomatoes.

 

 

The riser idea can be used with any plastic container that has the recessed lid problem of catching rain. Also, even though it has wheels, do not hope to move the tote after is has been filled. It will weight well over 200 pounds and will not budge.