Grow: Indoors Passive Hydroponics Kratky

There are many different methods of growing a variety of plants and veggies inside the house during winter months. We’re about to get our first deep freeze this week and that means I’m harvesting my outdoor crops and covering my potted swiss chard on the porch in the hopes it survives the night.

I also want to grow a few fresh things over the winter. Here in Mass, that means I need light and warmth. In my case, it also means I need to find a space. Given we have 1200sq ft of living space that means I’m going to need to be creative in the living space and use a spot in the basement.

Fortunately, part of “Project Ferment” meant cleaning out the basement shelves and moving things around. That project isn’t totally finished but it is getting there. Eventually, we are switching the house over to natural gas and the oil tank will be removed, giving ma a whole corner of the basement I can use for storage and planting. For now I have a large oil tank taking up space. So I’m limited to a smaller shelf than I would like, my plan is to put in a 10×10 pop up growing tent in that space.

An option for folks like myself with very little space is something like an AeroGarden. There are many different models of AeroGarden but they all involve a compact container for nutrients, some sort of plant cup, and a LED or fluorescent light. The basic AeroGarden is Kratky style it uses power for the LED but the solution isn’t circulated or aerated.

My goal this winter is to create a DIY and 100% recycled version of the Kratky or passive hydroponic system.

To create the plant container of net cup, I’m using recycled K-cups. I hate Keurig with a burning fiery passion for their pollution with these plastic and tin pods. We don’t use them in our home but they are used at my workplace. I sat a box out and asked folks to toss used cups in, they did. I’ve been collecting 3 or 4 a day.

K-cups are 38mm across the base. A Jiffy 36mm peat pellet windowsill garden makes a perfect container to hold these as they sprout.

After collecting the k-cups they need to be emptied. The hot cocoa and chai cups are the easiest as they have no filter or coffee. To clean a cup use a sharp knife to slice away the aluminum covering. The sharper the knife the faster this goes. I slide my knife along the edge of the cup and the aluminum slices cleanly.

I then use a spoon to get the spent coffee grounds out of the pod. I am then able to poke and pull at the filter, it removes with some work. When wet these do not slice cleanly even with a sharp knife. So I rely on my finger to tear the paper. I use a knife to scrape out any remaining fibers. It does not have to be perfect.

I wash and rinse the cups. Once dry I use a sharp craft knife to slice the bottom. I’ve settled into 2 or 3 cups on the bottom edge of the cup and several vertical slices along the sides. Once a bunch of cups are slices, I line the cups with newspaper. This keeps soil inside the cup during sprouting, helps wick water into the cup, and keeps things tidy for now. I accomplish this by wrapping newsprint around a cup and then pressing it into a receiving cup.

After I’ve got a few cups finished, I spoon soil in. I’m using organic indoor potting soil. You could use seed starting mix or whatever makes you happy. Each cup seems to hold about 2 heaping tablespoons full of soil. I do not pack the soil in but instead, keep it loose. The soil is then watered completely, and seeds placed about an inch deep. The containers with the pods are placed in a warm spot until all the seeds have started.

Next we’ll talk about the containers for the hydroponic solution and grow cycles.

Leave a Comment

Your email address will not be published. Required fields are marked *