General Hydroponics 3-part (Flora Series) nutrients are an excellent choice for DWC. They provide the Nitrogen, Phosphorous and Potassium your plants need to thrive. Different ratios are used throughout the growth cycle as the plants move from a nitrogen hungry vegetative phase to Phosphorous and Potassium heavy flowering stage. Organic fertilizers should not be used in DWC as they can introduce pathogens to the water solution. Microbes should only be introduced via a controlled beneficial microbe tea (optional).
The 1-quart pack will be enough to get you through a single grow if using a single reservoir and 2×2 or 3×3 tent.
The 1-gallon pack should be enough for 4-6x 240 Watt grow cycles or 2-3x 480 Watt grow cycles.
I recommend getting the gallon pack if you can afford it. You will end up needing more down the road. You will likely use 2x as much Bloom as you do Micro or Grow in DWC.
Pro Silicate – Supplementing silicate helps with cell wall strength and increase water uptake and even adds an extra level of protection against fungal diseases like powdery mildew. I strongly recommend it for anyone growing in DWC. Use during vegetative growth at 5mL per gallon. 1-Litre of Pro Silicate will last most micro growers a few years. ArmorSI is a suitable alternative if ProSilicate is not available.
The doc’s nutrient calculator makes it easy to mix up large batches of nutrients at a time. I find that a 250 mL graduated cylinder is the perfect size for measuring out large amount of nutrients. Who wants to measure out 30+ tablespoons for a 15 gallon batch? Not the doc.
General Hydroponics 3-part (1 quart pack)
1x 240 Watt Grow
480Watt Grow – buy extra quart of FloraBloom
General Hydroponics 3-part (1 gallon pack)
4-6… 240 Watt grow cycles
2-3… 480 Watt grow cycles
This is the General Hydroponics feed chart the above calculator is based on the recommended dosage by General Hydroponics. Some growers prefer to reduce this concentration but I have never had issues running it at full force. If you are growing in a low humidity environment or using outdated HPS lights it is possible that your plants will drink water faster and thus could experience nutrient burn. If you notice any burnt yellow tips on new growth reduce the quantities above by 50%.
General Hydroponics Flora series was first formulated in 1976 according to their website. I cannot confirm this date but the stuff has been around forever. I go through way more of the Bloom (red) than I do the Gro (green) or Micro (brown). This is because in DWC the plants fly through veg. They spend the most time in flower where they drink up the Bloom.
Strength – I almost always mix at 100% strength. They only time I would reduce the strength would be if (1) I see signs of nutrient burn (yellow crispy leaf tips) or (2) for low humidity (50% or less) situations where transpiration is high and the plant is drinking water faster. Most HPS growers need to reduce nutrient strength because the additional heat the bulbs put off increases transpiration.
Brown roots – Do not be scared of slightly brown roots when using General Hydroponics in DWC. Although typically brown roots are an indication of root rot in DWC, the Micro nutrient from the Flora pack has the tendency to colour the roots brown. This is harmless, and if your roots do not show other signs of root rot (like foul smell, falling off or turning black/very dark brown) there is no cause for concern.
Mixing Extra Nutrients in Advance – is something I typically do not recommend because this nutrient solution can foster the growth of bacteria that can lead to problems down the road. If you must mix more than your DWC reservoir holds follow the same rules of DWC growing. Keep the nutrient solution cold (below 60F), no light leaks, and use an airpump/airstone to keep it aerated.
Never Mix the Nutrients Together Without Water – Always add the Micro, Flora and Gro to the water container one at a time. Mixing the different solutions together without the presence of water to dilute them will cause solids to precipitate out. This will make it harder for the nutrients to dissolve into solution. I learned this the hard way when mixing a batch of nutrients into a jar for a friend who was growing outdoors. The result was a brick of ionic salts that was nearly impossible to dissolve.