Should I use Cal Mag with RO Water?

[ChrisSoiCy203]

Many growers rule of thumb is Feed nutrients every other watering. But determining when to start feeding and how much feed can be puzzling.

According to FoxFarms there is sufficient amounts of NPK to support 4 weeks of vegetative growth. The same recommendation is made for FoxFarms StrawBerryfields. After 4 weeks FoxFarms recommends beginning the feeding of Macro and Micro nutes. But then the question is : How much nutrients do I give the plant.

I use FoxFarm soil mixes Happy Frog (Veg) and FoxFarm StrawberryFields (Flower) and I adhere to that recommendation. I also use FoxFarms 3 part nutrients and the feeding amounts vary from plant to plant. Have you reviewed FoxFarms feeding recommendation charts ?

I also use Sensi CalMag. During vegetative stages I do not add CalMag to my HappyFrog soil mix. After transplanting into StrawBerryFields (5 gallon bucket) at on-set of flowering I begin to add 2mg CalMag per gallon with every watering and feeding. I've found that to work well for me during flowering.

How do you buffer your RO water with calmag if you wait till you transplant before you start adding calmag?

 

[ChrisSoiCy203]

I add calmag to every watering.

I use 50/50 mix of FF Happy Frog and Ocean Forest. I don’t start feeding nutrients until 4th week of waterings.

I feed nutrients every other feeding if I can water twice a week, otherwise I will feed nutrients every watering at half dosage if I’m watering once a week.

If you alternate your feedings or feeding nutrients everytime, if you’re using RO you MUST introduce calmag in every feeding until the last weeks of flower.

Do you add calmag even when they’re seedlings the first couple weeks with RO water?

 

[SchwiftyGrower]

Do you add calmag even when they’re seedlings the first couple weeks with RO water?

No I only add calmag when Veg starts. Solo RO water with HF soil for the first 14 days of breaking ground

 

[lowodorisbest]

I would, because in an amended soil like Happy Frog, you'll be feeding so infrequently that you won't be able to keep up with the magnesium demands. I'd give calmag with every non-feed watering through the end of the stretch, and a mag sulfur supplement after that.

Ive grown in Happy Frog three times using RO water, Fox Farm Nutrients and later moved to Dynagrow. Week 6 flower is always a problem for me using nutrients alone, I made it to harvest but had slight calcium/magnesium deficiencies everytime. I now use a Cal Mag supplements "lightly" on top of my nutrient feed schedule.

I use Dynagrow Mag Pro as well, great stuff if you ask me. (covering your mag sulfur supplement mentioned above.). Good advice !

Note: Happy Frog is great stuff. BUT, I have to boil and cook the soil here on the east coast or I get Fungun Gnats everytime. (They call it Happy Gnats in many forums) You can also use BTI to get rid of the gnats, but I'd recommend cooking the soil first ---- If any root aphids eggs are in the soil, your gonna be hating life... Yes, you kill a lot of beneficial things in the soil baking it, but the trade off is worth it if you ask me. You can always add Mycos etc... later to get the soil "living" again. I'd rather it be sterile without bugs to start off.

 

[LoveGrowingIt]

BUT, I have to boil and cook the soil here on the east coast or I get Fungun Gnats everytime. (They call it Happy Gnats in many forums)

I understand fungus gnats are fond of soils that contain wood, and Happy Frog has wood chips in it. Boiling seems like a lot of work, but certainly would be effective. I've noticed the gnats begin to appear around a day after watering, while the top of the soil is still moist. So, I keep a spray bottle with a hydrogen peroxide solution (about 2 to 1 H2O to H2O2) ready. It kills them on contact. After killing the first wave of hatchlings with the H2O2, I spread diatomaceous earth over the surface of the soil. That kills them as they continue to crawl out of the soil.

 

[lowodorisbest]

I understand fungus gnats are fond of soils that contain wood, and Happy Frog has wood chips in it. Boiling seems like a lot of work, but certainly would be effective. I've noticed the gnats begin to appear around a day after watering, while the top of the soil is still moist. So, I keep a spray bottle with a hydrogen peroxide solution (about 2 to 1 H2O to H2O2) ready. It kills them on contact. After killing the first wave of hatchlings with the H2O2, I spread diatomaceous earth over the surface of the soil. That kills them as they continue to crawl out of the soil.

Get this and I guarantee your fungus gnats will be gone. BTI (Mosquito Bits).. You make a tea, water and ALL fungus gnats and larvae die. Your approach may work, but your killing a lot of good stuff too using Hydrogen Peroxide.

https://summitchemical.com/products/mosquito-bits/

Boiling soil is a bit of a hassle, but not that bad. I just use a 5 gallon pot, add boiling water until well soaked and bake in the over till 180 degrees. My fly traps in my grow cabinet show NO flies at all...Not the case if I dont sterilize the soil first.

Also, just one last tip with Happy Frog, it does have a tendency to get compacted pretty bad- I add 1/4 perlite to help combat soil compaction and have since moved to Fox Farm Coco Loco which is a mix of Coco and Fox Farm soil.. It drains so much better than Happy frog and my roots are much healthier. Happy Frog can smother/choke roots if your not careful....Especially in larger pots.

 

[ArtfulCodger]

Note: Happy Frog is great stuff. BUT, I have to boil and cook the soil here on the east coast or I get Fungun Gnats everytime. (They call it Happy Gnats in many forums)

Yep, it always (usually?) has gnats. I dry mine out for a month, in a tub under a tent exhaust, stirring every few days. Then I mix in a cup or two of diatomaceous earth when I pot up. That generally does the trick, and the DE is added silica.

 

[Brizzy420]

Hello, I’m preparing my first full indoor grow and am going to be using happy frog soil with added perlite and advanced nutrients ph perfect grow, micro, bloom. For watering i’m planning on using store bought refillable RO water. Will I need to use additional Cal Mag in my waterings or will the advanced nutrients and soil take care of it for me?

Most likely yes. I would add 2 ml per gallon every feeding. Plants suck up cal mag and iron especially after defoliation and stress training

 

[Natep]

The cleaner water is the harder it gets to measure ph and ppm. When water gets really clean RoDi it has to be measured in megaohms. It sounds like for your need you would be better off with a small two stage filter with a carbon and sediment. This would remove the chlorine from the water and some minerals but not all.