General Hydroponics in Kratky

General Hydroponics is the old man in the hydro game. Reliable, inexpensive, and available at all hydro stores, they make a great choice for your base nutrient solution. That said, you won’t see General Hydroponics in Kratky growing articles, with most choosing to use a MasterBlend nutrient system. It’s not very surprising, as the MasterBlend mix is less expensive.

That said, many of us keep GH products around, and purchasing an additional fertilizer mix makes no sense. As such, let’s define our problem.

Determining nutrient goals

We want to create a base nutrient solution that we apply to a wide variety of plants. We should then dilute this solution as needed to meet the needs of the plants we are currently growing. The simplest way to handle this is subdivide plants into the major growing categories where changing feed ratios makes sense. For me, that comes down to:

  • Herbs and leafy plants – These need a lot of Nitrogen, and moderate concentrations
  • Most other fruiting plants – Will require much more phosphorus and potassium than the leafy plants
  • Hot Peppers – They require fairly high concentrations of nutrients but relatively low levels of nitrogen

Additionally, we take into account that Kratky works better with more dilute nutrients, so we set our target to be about 25% less than what you would use in more traditional hydroponic grow systems.


Leafy vegetative formula

Use this for leafy vegetables, herbs, or to accelerate growth before fruiting

  • Flora Series – 12ml Micro, 12ml Grow, 3ml Bloom
  • MaxiGrow – 1tsp/gal

Dilute in half for seedlings, and to top up the res. Some oily plants, like mint or rosemary, thrive on a stronger concentration. You can safely go to about double concentration with those plants.

General flowering and fruiting formula

Plans in soil and Kratky in my indoor garden.

Use this to get your tomatoes, cucumbers, or whatever fruiting plant going.

  • Flora Series – 12ml Micro, 10ml Grow, 7ml Bloom
  • MaxiSeries – 1 tsp/gal MaxiBloom+ 1/2 tsp/gal MaxiGrow

This provides about 1000ppm of strength and is suitable for most flowering and fruiting plants.

Hot Peppers

I take this as a separate because they need much stronger concentrations of nutrients to get the right flavor out of the peppers. However, getting them to fruit when there are high nitrogen amounts in the feed can be difficult, and if your goal is more peppers, limiting vegetative growth is important. Switch to this when your plant is at your target size:

  • Flora Series – 10ml Micro, 0ml Grow, 40ml Bloom
  • MaxiBloom – 1 3/4 tsp/gal

Other additives to use with General Hydroponics in Kratky

Gen Hydro’s product line is packed with a few other goodies you may want to use to help manage growth better. We use the following:

  • RapidStart – This is rooting hormone and a blend of vitamins to get the plant to grow more and healthier roots. Use it early in the grow at 2.5ml/gal to motivate your plant to grow more roots early on so the rest of the grow goes faster. I would recommend you use this mostly on fruiting plants. As this is an expensive additive, I wouldn’t go wild with it. GH’s feed plan seems to use it in a lot of growth stages, but I have found it unnecessary after the first few weeks.
  • Liquid KoolBloom – This PK booster encourages your plants to grow bigger flowers/fruits. If you have a healthy fruiting plant, a dose of this at about 1-5ml/Gal will probably boost production.
  • FloraliciousPlus – Ridiculous name aside, this humic acid supplement increases nutrient uptake and generally increases production. It’s priced like it’s made from ground unicorn horn, but the application rate is, thankfully, small. We use about 1ml/gal during flowering.
  • Floralicious Grow – This is a fluvic acid product that enhances vegetative growth. It’s nice. It’s reasonably priced. If you want your lettuce faster it’s a good investment. Alternatively, Diamond Nectar serves the same role.

I hope these formulas give you a good starting point in your experimentation. Good luck.

2 years ago