Growing in promix HP, watering and feeding feedback

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Jakeallenmissed

Jakeallenmissed

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Okay friends please help me out, I've tried to research on my own but either the advice has too much jargon for the newbie that I am or it's not advice tailored to my grow.

Details To know...
Mars hydro LED
Pro-mix HP medium mixed with 30% worm castings (most have suggested that's a bit much, some suggested I don't use EWC at all...)
Using a 3-1-3 nute (iguana juice, switching to bloom at flowering stage)

Packaging says mix 4 ml per liter per so I do about 14-15 per gallon but the more I read the more I hear people say go ahead and half that.

Temp is 75-80 lights on, 66ish lights off with a 18-6 light schedule
Humidity is around 50%
I'm growing autos (I know I know, I've chosen a tough road)

This is my first grow, there is a ton of advice out there saying don't over water so at first I watered so little that I was clearing stressing the plants. I then upped to water every other day schedule, the 4th day watering with nutes, I then saw clear signs of over watering so switched to every 3 days but now with nutes in water every time.

So my question is, when using pro mix hp how often do you water? Do you include nutes in your watering every time?

Do you test the ph of your mix before feeding, if so are you shooting for the 6.2 6.4?

I've seen printed schedules but I have a bit of trouble understanding them and finding one that applies to me.

I'll attach a pic of my healthiest plant and my least. I believe my least healthy one suffered Most From my early mistakes and have recovered a bit since but she ain't pretty.

Any advice you have around promix is appreciated. I'm exploring coco grow too but I'm really enjoying the pro mix hp.
 
jguit

jguit

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So my question is, when using pro mix hp how often do you water? Do you include nutes in your watering every time?

Do you test the ph of your mix before feeding, if so are you shooting for the 6.2 6.4?
I water promix hp when the pots start to feel light in weight. It really depends on the size of the plant and pot but in my situation, I find myself watering approximately twice a week.

I don't test the ph of my mix as I know after mixing the pH of my feeding solution will be around 6 or so.. As long as your pH isn't ridiculously high or low, it really doesnt matter much.

As for how much you feed, it really depends on how often you water and what your plants need. If you're only watering once a week, you can probably feed full strength nutrients every watering. If you're watering multiple times a week, you'll probably want to feed say, 75% strength or maybe get on a Feed/Water or Feed/Feed/Water schedule. Schedules from fertilizer companies are just guidelines.
 
Dirtbag

Dirtbag

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I do "feed feed water" cycles in promix. I never use worm castings in it though as it will ruin its drainage properties and make it acidic. Actually that's not completely true, I used to use one cup of castings in 10 gallons of soil, but its a trivial amount. Much more than 15-20% will cause issues in promix.

It's important to let it get really dry before watering, and when you do water be sure to fully saturate the pot until you get some runoff. I generally feed about 1-1.3ec, ph of 6-6.3.
 
Jakeallenmissed

Jakeallenmissed

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I water promix hp when the pots start to feel light in weight. It really depends on the size of the plant and pot but in my situation, I find myself watering approximately twice a week.

I don't test the ph of my mix as I know after mixing the pH of my feeding solution will be around 6 or so.. As long as your pH isn't ridiculously high or low, it really doesnt matter much.

As for how much you feed, it really depends on how often you water and what your plants need. If you're only watering once a week, you can probably feed full strength nutrients every watering. If you're watering multiple times a week, you'll probably want to feed say, 75% strength or maybe get on a Feed/Water or Feed/Feed/Water schedule. Schedules from fertilizer companies are just guidelines.
I think reducing my mix Strength will do wonders, I've already started experimenting with it and have been getting good results. Thanks for the feedback
 
Jakeallenmissed

Jakeallenmissed

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I do "feed feed water" cycles in promix. I never use worm castings in it though as it will ruin its drainage properties and make it acidic. Actually that's not completely true, I used to use one cup of castings in 10 gallons of soil, but its a trivial amount. Much more than 15-20% will cause issues in promix.

It's important to let it get really dry before watering, and when you do water be sure to fully saturate the pot until you get some runoff. I generally feed about 1-1.3ec, ph of 6-6.3.
So...

How often between water/feedings? Or are you just waiting for it to dry every time?

Do you saturate when you do your feed? (So you pattern would be.. feed...dry... feed.... dry.... water.... dry... and so on?)

How dry is dry to you? I've heard people panic about going full dry (though most of those concerns are with coco)
 
jguit

jguit

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You let it get fairly dry between waterings but not dry enough that you plants start to droop heavily. In veg, letting them droop a little is fine but in flower weight of the buds can cause havoc if you let them droop too much. You'll find that your plants will get on a fairly consistent watering schedule. Judging by the weight of your pots is a pretty good indication on when to water.

When your plants have an established root system you'll want to saturate it and get a little bit of runoff but if your root system isn't established it'll take forever to dry and potentially cause root problems. That said, your root system should get established fairly quickly.
 
Last edited:
Frankster

Frankster

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What dirtbag said. Yes saturate when you feed, then dry the pot out (sometimes a day, sometimes 1.5, or 2 days) Dry stressing is healthy up to a point. It's good for resin production, and it's good for your soil health, your fungi (sponges) down there will hold the plant up when the water is almost gone.

I would keep things lower, around 6 or like Dirtbag suggest, because your pH is going to rise on it's own during nitrification process within the soil itself.

A little droop is ideal, a lot of droop or completely down is bad
Don't panic, unless the leaves are down, then back off the light for a few hours, and rehydrate. Mist them lightly, if there really down.
 
growsince79

growsince79

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What dirtbag said. Yes saturate when you feed, then dry the pot out (sometimes a day, sometimes 1.5, or 2 days) Dry stressing is healthy up to a point. It's good for resin production, and it's good for your soil health, your fungi (sponges) down there will hold the plant up when the water is almost gone.

I would keep things lower, around 6 or like Dirtbag suggest, because your pH is going to rise on it's own during nitrification process within the soil itself.

A little droop is ideal, a lot of droop or completely down is bad
Don't panic, unless the leaves are down, then back off the light for a few, and rehydrate.
Do you promix guys add extra perlite? I'm trying promix hpcc and thinking I shouldn't have added perlite. I have to water every day now.
 
Frankster

Frankster

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Do you promix guys add extra perlite? I'm trying promix hpcc and thinking I shouldn't have added perlite. I have to water every day now.
My advice would be no, (maybe others can speak on this with more authority) I don't use promix, but going to high on the perlite can cause some major issues from what I hear. Making soil drain far too quickly.
 
Frankster

Frankster

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This is a little different but in the same vein. I spray these gals everytime I go by them for the most part. The cups were watered days ago, but are still moist, so I leave the media alone.

Until those roots get started, I won't do hardly anything as far as adding water, only when almost bone dry, but I will feed them from the top side to keep them hydrated and inflated.

You don't have that luxury, because your in flower, so you cant feed from above, it will cause rot. So you must find a healthy balance.... Perhaps adding some air movement in the bottoms can help improve your situation.


Read this thread to understand water tables better: It's about coco, but the same exact principles apply here.
 
Jakeallenmissed

Jakeallenmissed

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I don't.. Once plants are established i find that i'm watering about every 2-3 days on average.. I'm using promix HP

My biggest hurdle when learning to grow with promix was overfeeding.
2-3 days on average seems right based on what I've been seeing. But I haven't really been saturating
 
Dirtbag

Dirtbag

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Really important to saturate fully with each watering. If time permits I actually like to water promix in 2 stages, I'll give the pot about half of its water and let it sit for 20 mins to soak it in and fluff up, then I give it the other half. Doing it that way helps prevent channeling and allows the water to penetrate the root ball better.

And I agree with jguit that feeding can be tricky to dial in. Especially in the first half of flower. Promix has a fairly strong nutrient holding capacity which can lead to toxic buildups, especially when the nutrient demands change due to shorter days and stretchy plants.
The last few times I ran promix I'd cut my feed way back to like 0.7 - 0.8ec for the first few weeks of stretch, and plenty of plain water every third feeding or so to prevent excess. Seemed to really help prevent that mid flower ppm spike that promix tends to do.
 
Frankster

Frankster

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Yea, I do that all the time, a little water here, a little water there, then come back and finish it off afterwards, to ensure complete saturation.

Basically it boils down to this IMO:

1) proper pot size for the appropriate plant developmental level.
2) complete saturation, that means pulling the plant out, feeding it, letting it drain on a tray, (not watering it the lazy way) turning it sideways (if necessary) to drain out the remainder, then re-position.
3) maintaining adequate air circulation within the environment so that good oxygen exchange can occur.
4) maintaining correct water table.

Visit the above thread, and you'll have a much firmer understanding of the fundamental process at work here. When you don't pull that plant out of the tent to water it, your leaving some of the roots dry, and that causes problems down the line.

This is my buddy for that situation.
 
Jakeallenmissed

Jakeallenmissed

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Yea, I do that all the time, a little water here, a little water there, then come back and finish it off afterwards, to ensure complete saturation.

Basically it boils down to this IMO:

1) proper pot size for the appropriate plant developmental level.
2) complete saturation, that means pulling the plant out, feeding it, letting it drain on a tray, (not watering it the lazy way) turning it sideways (if necessary) to drain out the remainder, then re-position.
3) maintaining adequate air circulation within the environment so that good oxygen exchange can occur.
4) maintaining correct water table.

Visit the above thread, and you'll have a much firmer understanding of the fundamental process at work here. When you don't pull that plant out of the tent to water it, your leaving some of the roots dry, and that causes problems down the line.

This is my buddy for that situation.
What is that in the picture? I've been looking for something them to drain into
 
Frankster

Frankster

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What is that in the picture? I've been looking for something them to drain into
6" 8" 10" 12" 14" 16" 18" 20" 25" Black Sturdy Indoor Plant Pot Container Saucer Thicker = Better.
The top part is a remnant of my air pots, cut for drainage. (I use cloth pots now).
 
boomgagem

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Thinking about using pro mix next grow. What would the best/easiest to use synthetic nutes to use for pro mix?
 
growsince79

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Jakeallenmissed

Jakeallenmissed

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6" 8" 10" 12" 14" 16" 18" 20" 25" Black Sturdy Indoor Plant Pot Container Saucer Thicker = Better.
The top part is a remnant of my air pots, cut for drainage. (I use cloth pots now).
Thanks! It sounds like you increase the size of the pot as the plant grows? Right now I use a nursery bag to start and then it's straight to a 5 gal grow bag. But I could see benefit in incrementing (saving water, improve availability, offer potential application of mycorrhizae such as great white)
 

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