I like yourself am retired , I live in Brisbane Australia and us ethe Kratky method of hydroponic growing. I have found that lettuce grows very well and other leafy vegetables.
I also use DWC, Drip , and ebb and flow methods , however the kratky method works very well and easy to use.
I have cut out holes in the top of my containers , where I place growing pots with expanded clay pellets, with just the tips of the roots touching the nutrients , so the seedlings will not drown, but encourages the roots to go deeper as the nutrient level drops.
As time goes by, I sometimes have to add new nutrients as depleted levels can leave the roots dry out, however I am careful not to add the nutrient levels too high.
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Thanks for the follow up post. How long did you grow plants in the Kratky system? I'm mainly interested in it for short term plants like lettuce and other greens. Do you think it poses more problems for long term use like with tomatoes or cucumbers?

Delaware I think you have hit it on the head, I grow asian vegetables and lettuce etc which do extremely well in the Kratky method which is where I use this method of hydroponics. As for tomatos which are very thirsty I do not recommend or other long growing to maturity plants .
I have also found that the Japanese vegetable Komatsuna grows very fast and is good in stir fries or soups, as do the cos variety of open head lettuce of which there are many varieties and colours to choose from. Keep me in the loop as to your success. PS lettuce etc only need very weak solutions of nutrients, and I take the easy and cheap way out with A and B powder nutrients which are cheaper and offer both flower and fruiting as opposed to buying bottles of liquid which is watered down and in the end costs a lot more.

I use HG 10-8-22 plus micronutrients- general purpose hydroponics nutrients and I got excellent results!

I still use the Kratky method, along with other methods, I grow my chinese vegetables and lettuce and greens using this method. For tomatoes, peppers etc and other thirsty plants I do not use as it means topping up the nutrients frequently . Another asian plant Kang Kong has a huge root growth and is a water plant ,and abundant roots take up a lot of the nutrient.

I prefer to use the Kratky method where I plant the seedlings and allow the roots to grow using the nutrients up and at the same time as the levels go down the strength increases which compensates with the plants growth, in other words young plants need weal solutions larger plants require stronger solutions. All plants can grow using the Kratky method even strawberries , but with strawberries they require frequent nutrient changes plus also the roots do not like being too deep in the nutrients or they will rot.

I grow the Kratky method in net pots with Leica (clay balls) or with the tiny net pots for my lettuce I use perlite which is a little messy, but with small seedlings and small roots I use perlite.

Great info Robert. I have heard that plants do not uptake all nutrients equally and it's better to change nutrients solution rather than top of or just let it go way down. I'm uncertain as I'm only growing short time greens crops but it's something to investigate further. What all are you growing these days?