How To Start Growing With The Kratky Method

Build a farm to fit personal & professional goals

When I told myself I’d no longer actively pursue an upward climb in my current career, and I would start my own business, I found myself spending hours each day on the internet consuming everything. The possibilities never seemed to end. After months of research, I was drawn to give aquaponics a try.

I built a small system to learn and practice with. It had about 20 goldfish in a 150-gallon tank. Over the course of a few months, I had success growing lettuce & herbs in a very small space. I learned the ins and outs of maintaining a well-balanced ecosystem via constant water testing. This was all great practice.

However, as time went on and after visiting a commercial aquaponic training course, the major risks started to show themselves. I saw that one electrical failure can lead to a total crop loss and loss of the fish population. Due to this, the system required constant monitoring. This lifestyle seemed just as restrictive as the job I was already in. Along with the high upfront capital requirements, this forced me to look elsewhere.

The more practical solution for my farm was hydroponics. Choosing a grow system from the dozens of techniques and variations just within hydroponics seemed to be an endless rabbit hole in itself.

At this point, I knew I didn’t want to kratky method make any large investments and I preferred a flexible schedule. I wanted to be able to learn, test my market and see what I actually liked doing without committing myself with to an expensive system.

In came the Kratky method.

By this time, I had also started to formulate what my business would actually look like. I was thinking of starting a food truck around the same time, so my idea was to combine them both: a ‘farm-to-food truck’ concept.

Farm-to-food truck

If I was going to be running a farm and a food truck by myself, I’d have to be very careful with time management. What I needed was an easy to learn and easy to maintain hydroponics approach, and that’s what Kratky is.

For those of you unfamiliar, the Kratky method (named after B.A. Kratky) is a passive growing method. This means that no pumps or electricity are needed during the growth cycle. A young seedling is placed onto a raft, similar to a standard hydroponic raft (DWC) system. The difference between this and a raft system is that in the Kratky method, the raft sits fixed atop a tank filled with water and nutrient solution which sits stagnant.

Throughout the growth cycle, the water level drops as the roots grow, creating a growing ‘air zone’ for the roots.

By the time the plant is ready for harvest, the nutrient water is nearly depleted. From here you can just replenish the water & nutrient solution and place fresh transplants on top of the tank. A spray down and vacuuming of the tank is needed after 3–5 cycles.

Unlike in recirculating hydroponic systems, Kratky growers calculate the amount of nutrient solution for each tank only once. The solution does not require additional adjustment.

This is a great benefit to a new grower who wants to keep things as simple as possible, just as I was looking for. I grow only leafy greens with Kratky, which gets a combination of an A and B solution. Solution A is a Chem-Grow lettuce formula + calcium nitrate, and Solution B is magnesium sulfate (Epsom salt), each mixed in with a specific amount of water. (Mixing instructions come with the fertilizers.)

To set up the system solution, growers can simply add solution A to a tank filled with water, mix, then add solution B. Place your rafts with transplants on it and you shouldn’t need to touch it again until it’s ready for harvest.

Note: If you’re interested in learning the details on raft construction and the proper amount of nutrients, the best source is from the University of Hawaii in the following paper- A Suspended Net-Pot, Non-Circulating Hydroponic Method for Commercial Production of Leafy, Romaine, and Semi-Head Lettuce.

As my business grew, all I had to do was build additional rafts. Each 4’x8′ raft fitting up to 60 heads of lettuce can be built in about 20 minutes using a few screws, plastic liner and (4) 2″x6″x8′ pieces of lumber (described in detail in the link above). This gave me peace of mind knowing I didn’t have to commit any significant financial investment to grow a bit bigger. I still could incorporate another grow style should I have the need or want to really ramp up production.

I can harvest the lettuce from the rafts in the morning, and by lunch, I can have them prepared into salads & smoothies. Because Kratky has no moving parts, it allows me a disaster-proof assuredness that other hydroponic methods don’t offer. Additionally, I can be away from the farm for hours or days, and I don’t have to worry about technology failing.


Post time: Oct-19-2021
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