HYDROPONIC GUIDELINES FOR ROCKWOOL USE

General Guidelines for Rockwool Use

Prepare rockwool by thoroughly soaking it to capacity with the proper nutrient solution.  Always apply  nutrients to the rockwool before handling the product.  If handling rockwool in a dry state, and working in confined spaces, use a nuisance mask.  (These precautions should also be applied to perlite and vermiculite horticultural products.)  Keep the rockwool growing medium moist – do not let the media dry out!  The soluble salt levels will be thrown out of balance if the moisture levels in the rockwool are too low.  A good rule of thumb is to keep the rockwool wet enough that nutrients will squeeze out easily.  Irrigate 20% to 30% more than needed to leach out excess soluble salts. Three watering cycles of ½ hour each spaced throughout the light period is sufficient.

 

Monitoring PH and Soluble Salts Levels is necessary throughout all growth stages when using rockwool.  When initially wetting rockwool use a PH level of 5.5 to 5.8 and ppm of approximately 500 ppm.  (If ppm meter is not available follow instructions of nutrient manufacturer.  (PPM should be increased to a maximum of 1000 ppm after root system has been established.  Using the higher nutrient levels can cause burning of plants and excessive build-up of salts in rockwool.

To realize the maximum potential of rockwool, testing of the nutrient solution within the slab should be done on a weekly basis.  Use a slab tester (syringe) to pull a sample from the rockwool.  The growth range of PH in hydroponics is 5.9 to 6.9 with 6.2 to 6.4 being the ideal range.

 

PH:  If the sample from the rockwool is higher than the ideal range, PH in the reservoir should be lowered.  If the sample PH reading is lower, PH in the reservoir should be raised until the ideal range is attained.  Plants in a vegetative phase cause PH to go up.  Plants in a bloom phase cause PH to go down.  If plants in various phases are being grown using the same reservoir average PH to keep rockwool within the 5.9 to 6.9 range is desirable.

 

Salts:  To perform ppm tests on nutrient samples taken from rockwool a ppm meter is necessary.  Soluble salts will build up during use of rockwool.  As the ppm raises about the 1000 ppm level (e.g., 1300 or 1400 ppm) a weaker solution may be used to gradually leach the rockwool and bring the ppm back to normal levels.  Rockwool should not be leached with plain water except under emergency conditions.

As you can see use of ppm meters, PH meters and slab testers take the guesswork out of nutrient application.  All are available through Green Thumb Hydroponic Supplies.  We recommend hydroponic nutrients specified for rockwool.

 

Temperature:  Rockwool and air temperature can range between 60° to 85°.  Temperature for propagation should be 70° to 75° until plants are rooted.

General Guidelines for Rockwool Use

Prepare rockwool by thoroughly soaking it to capacity with the proper nutrient solution.  Always apply  nutrients to the rockwool before handling the product.  If handling rockwool in a dry state, and working in confined spaces, use a nuisance mask.  (These precautions should also be applied to perlite and vermiculite horticultural products.)  Keep the rockwool growing medium moist – do not let the media dry out!  The soluble salt levels will be thrown out of balance if the moisture levels in the rockwool are too low.  A good rule of thumb is to keep the rockwool wet enough that nutrients will squeeze out easily.  Irrigate 20% to 30% more than needed to leach out excess soluble salts. Three watering cycles of ½ hour each spaced throughout the light period is sufficient.

 

Monitoring PH and Soluble Salts Levels is necessary throughout all growth stages when using rockwool.  When initially wetting rockwool use a PH level of 5.5 to 5.8 and ppm of approximately 500 ppm.  (If ppm meter is not available follow instructions of nutrient manufacturer.  (PPM should be increased to a maximum of 1000 ppm after root system has been established.  Using the higher nutrient levels can cause burning of plants and excessive build-up of salts in rockwool.

To realize the maximum potential of rockwool, testing of the nutrient solution within the slab should be done on a weekly basis.  Use a slab tester (syringe) to pull a sample from the rockwool.  The growth range of PH in hydroponics is 5.9 to 6.9 with 6.2 to 6.4 being the ideal range.

 

PH:  If the sample from the rockwool is higher than the ideal range, PH in the reservoir should be lowered.  If the sample PH reading is lower, PH in the reservoir should be raised until the ideal range is attained.  Plants in a vegetative phase cause PH to go up.  Plants in a bloom phase cause PH to go down.  If plants in various phases are being grown using the same reservoir average PH to keep rockwool within the 5.9 to 6.9 range is desirable.

 

Salts:  To perform ppm tests on nutrient samples taken from rockwool a ppm meter is necessary.  Soluble salts will build up during use of rockwool.  As the ppm raises about the 1000 ppm level (e.g., 1300 or 1400 ppm) a weaker solution may be used to gradually leach the rockwool and bring the ppm back to normal levels.  Rockwool should not be leached with plain water except under emergency conditions.

As you can see use of ppm meters, PH meters and slab testers take the guesswork out of nutrient application.  All are available through Green Thumb Hydroponic Supplies.  We recommend hydroponic nutrients specified for rockwool.

 

Temperature:  Rockwool and air temperature can range between 60° to 85°.  Temperature for propagation should be 70° to 75° until plants are rooted.

© Copyright. All Rights Reserved.