Usually, I will replace the nutrient at least once per week. In other types of DWC like the Kratky Method, you can keep it up to 3 weeks, but it’s better than you should check the solution regularly. When the pH is too low/too high, or the nutrient solutions completely change color, time to replace it.
When the plants are still young, the Rockwool needs to make contact with the nutrient solution and absorb the nutrients from it to water up to the plants. As the plants mature, the root system will develop, absorb more nutrients and the level of nutrient solution can be reduced.
Get some cheaps low-heat bulbs of CFLs, or the expensive but effective LEDs. You can also go with the fluorescent tubes.
The suggested pH level of all types of plants are from 5.5 to 6.5, depending on the growth phase, and species of plants grown.
Usually, vegetative crops or crops that are in a vegetative phase need pH in the upper end, while fruits or plants that are in a flowering period require the bottom end of the pH level suggested above.
What is the appropriate temperature of the nutrient solution?
An airstone connected with the air pump via the airline is placed in the reservoir.
Nutrients and water are added to it.
The plants are placed in net pots above the nutrient solution in the reservoir.
A net pot basically looks like a cup that is made from reusable and rigid plastic mesh. This mesh allows your plants to have a strong and robust root system. If you have a normal cup with a hole in the bottom, there will only be one direction for your plants’ roots to grow. But with net pot, you can actually have roots spreading out from all different areas of your net pot. This is very great because it promotes a vigorous root system.
Basically, if you grow outdoor with enough sunlight, it’s great when plants can have sufficient light and have some rest at night when the sun it down. But if you grow outdoor, or your place lacks enough sunlight, time to get some.
In water culture systems and other types of hydroponic systems, air pump and airstone are used to create air bubbles to the nutrient solution.
Some common questions when growing with DWC
There are a few disadvantages of the DWC system; however, the benefits really outweigh the negative factors, and these disadvantages can be put up with because any type of gardening requires maintenance. These disadvantages are:
Any types of mineral nutrients work well in the DWC. Many growers also use organic forms, and it still produces good results with some drawbacks. If you are an experienced hydroponic grower, you can go with the nutrients of your choices. But for starters, and for ease of growing but still get the best results, I recommend any nutrients made for Hydroponics (not the multi-purpose nutrient package for plants) and stay away from organic nutrients.
These don’t match the power of the HPS/MH combo or LEDs, but they make much less heat and cost very little. Be cautious though, high wattage CFLs will make an enclosed space pretty hot too! CFL bulbs can be kept as close as two inches from the plant and in fact should be kept as close as possible since their light is only useful for the first 6 inches or so from the bulb.
pH’ing Your Water:
After you’ve mixed all of your nutrients and supplements into your water, it’s important to ensure that the nutrient water is the correct pH so your plants are able to properly absorb nutrients.
How to Manage the Water Reservoir
75 degrees (+/- 5 degrees) is optimal. With this type of growing system, high temperature can be a huge problem (especially in warmer areas). Bacteria loves nutrients and warm water, so your reservoir will be the perfect place for them to reproduce if you can’t keep them out. There are two main ways to go about fighting bacteria/algae.
A lot of people recommend using 35% Hydrogen Peroxide to deal with root rot. I’ve had root rot quite a few times and tried 35% Hydrogen Peroxide to fix this problem. All I’ll say is that for me, it didn’t work even close to well enough for me to recommend it to anyone. Even if the roots seemed to be doing temporarily better after being treated with H2O2, the root rot would come back with a vengeance in only 1-2 days. SM-90 and Hydroguard (Hydroguard especially) are both methods I’ve used which will cure your system of root rot long-term and are highly recommended over using Hydrogen Peroxide.
Draining Reservoir Water:
If growing with CFLs, it’s best to get many small CFLs and spread them around your plant. Although there is some benefit to lighting the sides of your plant, cannabis plants tend to fatten the buds highest up on the plant, so you’ll usually get a better bang for your buck by focusing most of your light towards the top of the canopy where your biggest buds are located. Learn more about growing cannabis with CFLs.