If u follow this u shouldn't have problems also have u checked runoff ph as low ph means root rot what was seen on other plant u more than likely have it on all plants if your feed goes through each plant and can u not start your clones in rockwool. u shouldn't need to adjust ph and ec daily my friend grew hydro feeding from res hes was stable for 7 days he changed res once a week got 153oz off 15 plants the more u feed the more stable res will be i would feed at least twice a day it also suggests in this artical 3 to 4 times a day
It is a Hanna meter. I check the PH and PPM before every feeding which i do every other day.
GROWING CANNABIS IN ROCKWOOL
Rockwool, stone wool, or mineral wool has been the hydroponic substrate of choice for a number of decades. Beginning its life in general hydroponic horticulture, it proved to be an excellent medium for growing all sorts of plants. It was only natural then for existing methods to translate over into the world of weed.
“Rockwool” is one of those trademarks that went on to become the generic term for this type of product. Just like Velcro or Aspirin, which are also trademarks, Rockwool is used to describe most products under this umbrella, and often drops the capital "R"—much to the chagrin of the trademark holders.
Rockwool was first produced commercially by the Danish company Rockwool in the late 1930s. It is an industrial method of mimicking a naturally occurring substance called Pele’s hair
[1], which is produced when wind blows through molten lava.
When it's produced artificially, air is forced through a stream of molten basalt slag. The resulting “wool” is then pressed into different densities for different purposes. It can be used for sound/thermal insulation, and with its custom density, is ideal for growing plants hydroponically.
The modular nature of rockwool means never having to disturb
the root systems of plants. The small cubes neatly fit into the next size cube up and so forth, with the final position usually being a large slab that contains a number of plants. Rockwool is highly absorbent and retains water very well. The loose structure presents virtually no resistance to roots, allowing for very efficient plants.
These top tips for growing in rockwool will make sure your indoor grow is successful.
1. PREPARATION
Rockwool needs to be stabilised and prepared before using it to grow cannabis. Untreated, it has a pH of 7.0, which is too alkaline for healthy cannabis growth, as there are no naturally occurring buffers like with soil. When the substrate is too alkaline, there is poor nutrient uptake, especially of essential compounds like calcium and magnesium.
Soak the rockwool for 24 hours in a nutrient solution corrected to a pH of 5.5 with an EC of 0.4–0.5. This range will make sure that young plants get off to a solid start with no nutrient deficiencies.
To check if the rockwool is stabilised at the correct pH, drench with a 5.5 pH nutrient solution and test the runoff water with a pH meter. If the runoff remains at 5.5, the substrate is ready for use; if it is still too high, re-soak for a few hours and then test again.
4. GROWING IN ROCKWOOL
An automatic irrigation system is ideal for rockwool. The material is highly absorbent and distributes nutrient solutions evenly throughout the root zone before settling at the bottom. This moisture gradient is what makes rockwool such an ideal substrate for hydroponics.
Hand watering is okay, but be prepared for multiple visits to the grow room per day, and be careful not to overdo it.
Plants sit in a shallow film of nutrient solution 2–3mm deep. Rockwool should be at medium saturation levels in the very lower layers, and drier in the upper layers.
Lower roots feed from the film of nutrient solution, while upper roots are exposed to moist air and all the oxygen they can get for healthy transpiration. Rockwool is not supposed to be wet like a sponge, as this is the equivalent of submerging roots, which will kill the plant.
Rockwool can also be used to hold plants for DWC, and there is little salt buildup since at each irrigation, fresh solution forces old salts out and draws down more fresh air into the medium. At all stages, watch plants for any kinds of nutrient stresses and adjust nutrient solutions accordingly
5. VEGETATION
The rockwool is stabilised at 5.5 pH and with an EC of 0.4–0.5. During the early stages of vegetation, when plants are still small, irrigate for one minute to apply 60–70ml of nutrient solution twice per day. Once when the lights come on, then again halfway through the light cycle. This facilitates root growth and prevents water logging.
Watch plants for changes in nutrient demand as they grow and increase the amount of solution per plant as they get bigger. Continue this regime until the first week of flowering.
6. FLOWERING
• Week 1
Swap to a
flowering nutrient and gradually increase pH over a week from 5.5 to 5.8–5.9.
• Weeks 2 & 3
Increase the EC to 0.8–0.9 and the pH to 6.0. Increase the frequency of watering from twice a day to three times per day. Irrigate for two minutes when the lights come on, then for one minute six hours later, and for one minute prior to turning lights off.
• Weeks 4 & 5
Increase the EC to 1.0–1.2 and fluctuate the pH between 6.0 and 6.2 to ensure complete nutrient uptake. Increase frequency of watering to four times per day. Irrigate for two minutes at the beginning of the day, then for one minute at hours four and eight, then for two minutes again before the lights go off.
• Week 6
Increase EC to 1.4 and keep pH fluctuating between 6.0 and 6.2. Increase frequency of watering to six times per day. Irrigate for two minutes at the beginning and end of the day, and for one minute at regular intervals in between.
• Week 7
EC can be increased from 1.4 up to 1.6–1.7, and fluctuations in pH can rise to between 6.0 to 6.3. Keep the irrigation frequency the same as in week 6.
• Week 8
Continue as per week 7. Depending on specific strain demands, EC can be increased to 1.8.
• Weeks 9 & 10
Depending on strain, it is the last week of flowering for cannabis. Reduce EC to as low as possible and keep pH at 6.2. Keep irrigation frequency the same, but increase to two minutes at every watering.
During the final week is the time to thoroughly
flush your cannabis with a flushing product to remove all excess salt buildup from the root zone. Flushing improves the final aroma and flavour of the flowers prior to harvest.
