Remember, the goal of the reservoir is to provide ALL the nutrient water the plant needs over the course of its life. For cucumbers and zucchini this can mean 27-50 gallons (200 liters) as shown above. Some plants like peppers and tomatoes are actually grown as perennials in many parts of the tropics. Perennial plants are difficult to estimate their water needs since we aren't sure how many years the plant will live. Some people have written to me that tomatoes they were growing in 50-gallon drums ran out of nutrient water. I grow "Patio" tomatoes in a 10 gallon tote, but I also add a float valve as pictured below.
If you do not have room for large reservoirs but want to grow fruiting plants hydroponically, you can explore DWC or drip/Dutch bucket systems which can use much smaller containers.
If you do not have room for large reservoirs but want to grow fruiting plants hydroponically, you can explore DWC or drip/Dutch bucket systems which can use much smaller containers.
A float valve allows the grower to have an external secondary reservoir to hold additional nutrient water. This can be refilled without damaging the air roots of the plant.
I recommend a 1/4" float valve as the flow of nutrient water is small in these systems. |
This is one way to have a number of reservoirs for large plants that are all maintained at the same level with a single float valve.
The balance between nitrogen, phosphorus, and potassium is different as we move from vegetative growth to flowering & fruiting plants. Some people report Masterblend works fine in both growing situations. If you use the General Hydroponics Maxigrow nutrient for vegetative growth, switch to Maxibloom for your fruiting and flowering plants.
While many people can get by without measuring pH (a measure of the acidity or alkalinity of the nutrient water) and total dissolved solids (a measure of the concentration of nutrients in the solution) when growing vegetative plants like lettuce and herbs, it becomes essential to measure these two things when you start growing fruiting plants like cucumbers, squash, tomatoes, etc. Inexpensive dissolved solids meters like this one are okay to use but pH is much more difficult to get a reliable reading from inexpensive meters. Plants uptake nutrients most efficiently when the nutrient water is in the 5.5-6.5 pH range. If your budget is limited, I would recommend a color-based pH measuring solution kit like this. Inexpensive pH meters are on the market and I feel they cause more problems than they solve. I've recently upgraded to this Apera pH meter and so far, it is more reliable than the inexpensive pH meter. The top-of-the-line pH meters are those from Blue Labs. High quality pH meters usually come with calibration solution but it is also available separately as a powder or liquid calibration solution. Use every few months to ensure they're measuring accurately.
I use General Hydroponics pH Up and pH Down to regulate the pH but the brand is unimportant. I use pH Up much more frequently than pH Down. Do not use baking soda, lemon juice, and other household items in your hydroponic system. They are not as stable as the commercial products and may add undesirable elements such as sodium (in baking soda) to the nutrient water which can stress or kill the plants.
I use General Hydroponics pH Up and pH Down to regulate the pH but the brand is unimportant. I use pH Up much more frequently than pH Down. Do not use baking soda, lemon juice, and other household items in your hydroponic system. They are not as stable as the commercial products and may add undesirable elements such as sodium (in baking soda) to the nutrient water which can stress or kill the plants.
I aim for 500ppm for the "Easy plants" (on the Get Started page) and 1200 ppm for tomatoes with a pH of 6.0 for both.
These tables from Home Hydro Systems provide more detailed suggestions for concentration of nutrients (TDS) and pH.
These tables from Home Hydro Systems provide more detailed suggestions for concentration of nutrients (TDS) and pH.