Found some info I thought might be helpful. Below is two different guidelines for using Coco Growbags. These come from experienced growers who have been using Millenniumsoils Coir Growbags for many years. Keep in mind that these are all guidelines, and there will be variations depending upon your greenhouse, and location.
Guidelines for Millenniumsoils Coir Growbags
Preparing a fertilizer plan:
Fill a couple of slabs with clean water.
Let those stand for 24-hours.
Drain those slabs.
2 hours after draining ad some clean water on those slabs.
Catch this drain water for a water analysis.
Filling slabs:
Based on those numbers you make a fertilizer plan, without Potassium and 15% extra Iron and Manganese. Keep in mind the need for more Calcium.
Fill the slabs with this fertilizer plan.
Drip with an EC from 1.8 till 2.0 and pH from 5.6.
Drip till the slabs are saturated, or even a little bit overflowing out of the plant holes.
Drain the slabs after 12 to 24 hours.
Make sure that there are enough drain holes in the slabs, 1 between every plant, 1 at begin and end of the slab.
Drip after that, 1 litre a plant / dripper, with an EC value (fertilizer plan), which you like to start off in the crop.
After planting:
Bring 35% from the Potassium back in the fertilizer plan (based on a regular fertilizer plan).
Start off with a 0.2 higher drip EC.
Send after 2 weeks a new water sample out.
Make a new fertilizer plan on those results.
Give after planting in begin frequent water (short shots), so you prevent drying out of the blocks through the coco slabs.
When necessary to control the plant, you can stop with dripping water for a couple of days, when the plants are fully rooted in.
During the season:
Drip during the season with longer drip rounds.
Put always extra (15%) Iron and Manganese in.
Keep an eye on the 1st drain of the day, coco start draining when it is 100% saturated, this means coco drains average later (rock wool drains a little gradually).
Coco has over the average a higher pH (don't worry).
The plants grow on the average more vegetative on coco; adjust your climate to it.
Drip the double concentration of a pesticide on coco then rock wool, when you have to use it, because the organic structure of the slab, coco binds pesticide.
Stop on the average a little bit earlier with dripping at the end of the day then by rock wool.
Another Guideline for Millenniumsoils Coir Growbags
Charging of Coconut Coir Growbags
Coconut Coir is very high in Potassium, but low in Calcium. It is therefore necessary to charge the bag with high levels of Calcium to bring these levels in proper balance. To do this, charge solution is changed so that the amount of Potassium used is replaced by the same amount of Calcium Nitrate.
Eg. – If your solution required 200kg of Potassium Nitrate and 250kg of Calcium Nitrate, you would replace the 200kg of Potassium Nitrate with Calcium Nitrate. This would give you a total of 450kg of Calcium Nitrate and no Potassium Nitrate.
The bags are then filled until they are full of water, and left for approx. 48 hours or longer, if possible. They are then cut at the bottom of the bag as per your drain holes.
Once planted the feed solution will return to normal, however, it is recommended that the calcium level of the solution is increased by 20% for the first three weeks.
The recommended levels for pH and E.C. are as follows:
pH = 5.8 as the coconut has a tendency to be more acidic
E.C. = 3.5 – 4.0
Recommended Nutrient Levels for Cucumbers in Coconut (in ppm):
Chloride: 20 – 40
Nitrate: 250 – 350
Ammonium: 0.1 – 3
Sulfate: 300 – 500
Phosphorus: 50 – 75
Calcium: 350 – 450
Potassium: 350 – 450
Sodium: 10 – 40
Boron: 0.8
Iron: 1.2
Manganese: 0.5
Magnesium: 50 – 80
Copper: 0.05
Zinc: 0.4
Molybdenum: 0.05
These levels may vary based on your level of conductivity particularly in the major elements. Initially the pH in the bags may fall to levels below 5.0. This occurs as the organic matter in the bag begins to break down. Low pH has shown no adverse effects on the crop, but it is recommended that the feed pH be held on the higher side just below 6.0. as watering amounts increase the pH in the bag will also increase.
Watering Strategy
The watering strategy for Coconut Coir Growbags differs from that of rockwool growing medium. Due to the nature of Coconut Coir and its capillary action the bags should be watered at low frequency and higher duration times. Total water volumes will remain the same or slightly lower but delivery of the solution will be in larger volumes per watering.
In early crop plantings (November through mid January) it is recommended that moisture levels in the Growbags be kept low as root development in Coconut Coir can be quite rapid and large. This may result in Odeima if water levels are allowed to remain high in low light conditions. After the plant is put on the bag it is recommended that watering should occur only until the roots are established in the Growbag. Watering should then stop until the roots are thoroughly established in the Growbag, reaching the bottom of the bag.
Once this has occurred, normal watering may commence but with little leachate, about 10% maximum. When fruit development begins, water can then be increased to a 20% leachate. Water quantities per Growbag will depend on environment and plant development.
Guidelines for Millenniumsoils Coir Growbags
Preparing a fertilizer plan:
Fill a couple of slabs with clean water.
Let those stand for 24-hours.
Drain those slabs.
2 hours after draining ad some clean water on those slabs.
Catch this drain water for a water analysis.
Filling slabs:
Based on those numbers you make a fertilizer plan, without Potassium and 15% extra Iron and Manganese. Keep in mind the need for more Calcium.
Fill the slabs with this fertilizer plan.
Drip with an EC from 1.8 till 2.0 and pH from 5.6.
Drip till the slabs are saturated, or even a little bit overflowing out of the plant holes.
Drain the slabs after 12 to 24 hours.
Make sure that there are enough drain holes in the slabs, 1 between every plant, 1 at begin and end of the slab.
Drip after that, 1 litre a plant / dripper, with an EC value (fertilizer plan), which you like to start off in the crop.
After planting:
Bring 35% from the Potassium back in the fertilizer plan (based on a regular fertilizer plan).
Start off with a 0.2 higher drip EC.
Send after 2 weeks a new water sample out.
Make a new fertilizer plan on those results.
Give after planting in begin frequent water (short shots), so you prevent drying out of the blocks through the coco slabs.
When necessary to control the plant, you can stop with dripping water for a couple of days, when the plants are fully rooted in.
During the season:
Drip during the season with longer drip rounds.
Put always extra (15%) Iron and Manganese in.
Keep an eye on the 1st drain of the day, coco start draining when it is 100% saturated, this means coco drains average later (rock wool drains a little gradually).
Coco has over the average a higher pH (don't worry).
The plants grow on the average more vegetative on coco; adjust your climate to it.
Drip the double concentration of a pesticide on coco then rock wool, when you have to use it, because the organic structure of the slab, coco binds pesticide.
Stop on the average a little bit earlier with dripping at the end of the day then by rock wool.
Another Guideline for Millenniumsoils Coir Growbags
Charging of Coconut Coir Growbags
Coconut Coir is very high in Potassium, but low in Calcium. It is therefore necessary to charge the bag with high levels of Calcium to bring these levels in proper balance. To do this, charge solution is changed so that the amount of Potassium used is replaced by the same amount of Calcium Nitrate.
Eg. – If your solution required 200kg of Potassium Nitrate and 250kg of Calcium Nitrate, you would replace the 200kg of Potassium Nitrate with Calcium Nitrate. This would give you a total of 450kg of Calcium Nitrate and no Potassium Nitrate.
The bags are then filled until they are full of water, and left for approx. 48 hours or longer, if possible. They are then cut at the bottom of the bag as per your drain holes.
Once planted the feed solution will return to normal, however, it is recommended that the calcium level of the solution is increased by 20% for the first three weeks.
The recommended levels for pH and E.C. are as follows:
pH = 5.8 as the coconut has a tendency to be more acidic
E.C. = 3.5 – 4.0
Recommended Nutrient Levels for Cucumbers in Coconut (in ppm):
Chloride: 20 – 40
Nitrate: 250 – 350
Ammonium: 0.1 – 3
Sulfate: 300 – 500
Phosphorus: 50 – 75
Calcium: 350 – 450
Potassium: 350 – 450
Sodium: 10 – 40
Boron: 0.8
Iron: 1.2
Manganese: 0.5
Magnesium: 50 – 80
Copper: 0.05
Zinc: 0.4
Molybdenum: 0.05
These levels may vary based on your level of conductivity particularly in the major elements. Initially the pH in the bags may fall to levels below 5.0. This occurs as the organic matter in the bag begins to break down. Low pH has shown no adverse effects on the crop, but it is recommended that the feed pH be held on the higher side just below 6.0. as watering amounts increase the pH in the bag will also increase.
Watering Strategy
The watering strategy for Coconut Coir Growbags differs from that of rockwool growing medium. Due to the nature of Coconut Coir and its capillary action the bags should be watered at low frequency and higher duration times. Total water volumes will remain the same or slightly lower but delivery of the solution will be in larger volumes per watering.
In early crop plantings (November through mid January) it is recommended that moisture levels in the Growbags be kept low as root development in Coconut Coir can be quite rapid and large. This may result in Odeima if water levels are allowed to remain high in low light conditions. After the plant is put on the bag it is recommended that watering should occur only until the roots are established in the Growbag. Watering should then stop until the roots are thoroughly established in the Growbag, reaching the bottom of the bag.
Once this has occurred, normal watering may commence but with little leachate, about 10% maximum. When fruit development begins, water can then be increased to a 20% leachate. Water quantities per Growbag will depend on environment and plant development.
