Plants can’t survive from water alone; they need nutrients as well. In traditional growing, the plants will often get what they need from the soil (and even then you often still add fertilisers). But hydroponics removes the soil. Instead you need to use hydroponic solutions with the correct ratios of nutrients; too much or too little and your plants will suffer and potentially die!
I use General Hydroponics Combo Ferilizer pack for my hydroponics. In fact a lot of people recommend this brand. This brand has split the different nutrients a plant needs into different bottles. Plants need different amounts of various nutrients depending upon their growth stages; and the General Hydroponics Combo pack comes in three bottles that each contain different concentrations, allowing you to target each growth stage and get maximum growth and yields!
The Ratios
Mix the following amounts of nutrients into one gallon, or 3790ml, of water. I recommend filtered water to help reduce debris and other microbes from entering your hydroponic systems.
All nutrient measurements are taken in teaspoons.
| Gro | Micro | Bloom | |
| Seeds & Cuttings | 1/4 | 1/4 | 1/4 |
| Vegetative Growth | 3 | 2 | 1 |
| Late Vegetative to Pre-Bloom | 2 | 2 | 2 |
| Bloom to Fruiting | 1 | 2 | 3 |
I use the vegetative ratios of 3-2-1 for my Kratky lettuce since its main goal is to grow vegetation and leaves. Ideally I don’t want my lettuce to bolt and flower as the leaves will turn bitter.