Pro mix HP wont drain properly

R

retiredcarp

Member
I am using 3 gallon fabric pots for my autoflowers and I have been using nutes for 4 weeks now. I try to get some runoff (unsucessfully) but it takes 1 and 1/2 gallons to get any runoff! They just started showing signs of salt buildup so i took a drastic measure and flushed them with Flawless Finish ( which AN told me NOT to do after I already did it) I used 1 gallon per plant ( i have 6 ) and only got 5% if that off of 2 of the 6
This is way too much water/nutes and they will take a week to dry out for another watering/feeding
I assumed that the HP version of pro mix had enough perlite to drain better than its doing now
I am going to end up drowning my plants trying to get the 10-15% runoff that your supposed to
What am i doing wrong? I have fans on top and bottom and plenty of fresh air intake. RH is 50% temps are 78-82 degrees
Should i be adding additional perlite to my soil on the next crop?
How much more perlite should i add to get runoff with 3 quarts of water? (using the 1 quart per gallon of soil ratio)
 
chuckeye

chuckeye

Well-Known Member
I'm using ProMix HP straight out of the bale.

When I was using 3 gallon fabric bags a gallon of feed/water would barely produce any run off.

What you are doing wrong is fully watering before the plants are ready.

You should only be giving as much as they can use in three or four days. Depending on the strain it might take a month before they are ready for a full water.

A gallon and a quarter-ish will give you the run off you are looking for.

A "flush" would be 3X that amount.

Cheers
 
R

retiredcarp

Member
I use promix HP straight out of the bail also, I use nutes at every watering and was told by AN and lots of other growers that if you dont nute to a 10-15% runoff the soil gets salinated and causes lots of problems. You are supposed to start doing this when your roots are established and at 4 weeks with autoflowers, the roots are established
your technique is exactly how I have been watering them till now. And without providing runoff, my soil gets the salt buildup that ruins plants. and that is whats happening with mine
My original question was why does it take soo much water to get runoff with a soil that is supposed to be high porosity?? Most people say add some more perlite
 
jimihendrix1

jimihendrix1

Well-Known Member
Because even though its light, and gives good aeration, it still has Sphagnum Moss in it, and holds water.

I use the Promix BX and I rarely water till tun off. I dont use fertilizer at full strength either. I use about a 40% maximum recommended does of fertilizer, and feed them every time I water, and never have salt buildup problems. If youre having salt buildup problems, Id say to feed them less fertilizer, and dont use so much water. I usually have to water every 3 and a half days with temperatures of 80f-84f degrees, and fans blowing.
In a 5 gallon pot I dont use over 1 gallon-1.25 gallons of water at the maximum amount, when they are mid bloom, and growing like hell. I dont use the same nutrients as you, but I dont see how there would be any difference.

My advice would be to use less fertilizer, and dont use so much water. From what Ive read, at the maximum watering, you should use 20%-25% water to amount of medium. This may be different for Living Soil, as Ive not used that method. This is a general rule for Peat Based Medium. Temps, and airflow also have to be accounted for.

20% of 3 gallons is .6 of a gallon.
25% of 3 gallons is 3/4 of a gallon.
 
chuckeye

chuckeye

Well-Known Member
retiredcarp said:
I use promix HP straight out of the bail also, I use nutes at every watering and was told by AN and lots of other growers that if you dont nute to a 10-15% runoff the soil gets salinated and causes lots of problems. You are supposed to start doing this when your roots are established and at 4 weeks with autoflowers, the roots are established
your technique is exactly how I have been watering them till now. And without providing runoff, my soil gets the salt buildup that ruins plants. and that is whats happening with mine
My original question was why does it take soo much water to get runoff with a soil that is supposed to be high porosity?? Most people say add some more perlite
Click to expand...
Geez, it takes what it takes. I'm on my 3rd (?) version of bags, they are all slightly different and do not hold exactly 3 gallons.

Measure your water and keep adding until you get the run off you want. Done.

I would be looking at what ppm's are you feeding ? Salt buildup at 4 weeks is overfeeding...

ProMix HP has been my go to medium for years and I don't water to run off, at least not on purpose ;)

AN, Mega Crop and GH Maxi series. All work as well without run off or flushing.

But I am careful to read my plants and not increase their feed until they ask for it.

Long story, short. The bottom fan leaves will start to yellow. Up the feed by .5g/4L.

Burnt tips, back off.

When I was using AN M/G/B anything over 1000 ppm was too much...

Cheers
 
OldMedUser

OldMedUser

Well-Known Member
You guys having problems are doing something wrong or your fabric bags or nutes suck. I've used HP for 15 years, never have runoff because I just water to saturation. If I'm putting a clone in a 4gal pot I soak the pot and might not have to water again for 3 weeks. No sprinkling on the top either.

Soak, let dry, soak, let dry. Easy-peasy. AN 3-part in RO water kills in straight HP.

:peace:
 
OldMedUser

OldMedUser

Well-Known Member
retiredcarp said:
My original question was why does it take soo much water to get runoff with a soil that is supposed to be high porosity?? Most people say add some more perlite
Click to expand...
It already has almost too much perlite as peat moss is very porous too. It holds more water than dirt per volume so has to be truly saturated before runoff happens.

:peace:
 
thumper60

thumper60

Well-Known Member
retiredcarp said:
I am using 3 gallon fabric pots for my autoflowers and I have been using nutes for 4 weeks now. I try to get some runoff (unsucessfully) but it takes 1 and 1/2 gallons to get any runoff! They just started showing signs of salt buildup so i took a drastic measure and flushed them with Flawless Finish ( which AN told me NOT to do after I already did it) I used 1 gallon per plant ( i have 6 ) and only got 5% if that off of 2 of the 6
This is way too much water/nutes and they will take a week to dry out for another watering/feeding
I assumed that the HP version of pro mix had enough perlite to drain better than its doing now
I am going to end up drowning my plants trying to get the 10-15% runoff that your supposed to
What am i doing wrong? I have fans on top and bottom and plenty of fresh air intake. RH is 50% temps are 78-82 degrees
Should i be adding additional perlite to my soil on the next crop?
How much more perlite should i add to get runoff with 3 quarts of water? (using the 1 quart per gallon of soil ratio)
Click to expand...
Been using promix hp 40 plus yrs it takes 120oz to get 10 percent runoff in a 3 gal pot,Would like to see a pic of the autos if it takes a week to dry back plant is to small for the pot. my photo plants in 3 gal pots are bone dry in 24 hrs. Once plants are in flower i need runoff or all kinds of problems pop up.
 
R

retiredcarp

Member
jimihendrix1 said:
Because even though its light, and gives good aeration, it still has Sphagnum Moss in it, and holds water.

I use the Promix BX and I rarely water till tun off. I dont use fertilizer at full strength either. I use about a 40% maximum recommended does of fertilizer, and feed them every time I water, and never have salt buildup problems. If youre having salt buildup problems, Id say to feed them less fertilizer, and dont use so much water. I usually have to water every 3 and a half days with temperatures of 80f-84f degrees, and fans blowing.
In a 5 gallon pot I dont use over 1 gallon-1.25 gallons of water at the maximum amount, when they are mid bloom, and growing like hell. I dont use the same nutrients as you, but I dont see how there would be any difference.

My advice would be to use less fertilizer, and dont use so much water. From what Ive read, at the maximum watering, you should use 20%-25% water to amount of medium. This may be different for Living Soil, as Ive not used that method. This is a general rule for Peat Based Medium. Temps, and airflow also have to be accounted for.

20% of 3 gallons is .6 of a gallon.
25% of 3 gallons is 3/4 of a gallon.
Click to expand...
thumper60 said:
Been using promix hp 40 plus yrs it takes 120oz to get 10 percent runoff in a 3 gal pot,Would like to see a pic of the autos if it takes a week to dry back plant is to small for the pot. my photo plants in 3 gal pots are bone dry in 24 hrs. Once plants are in flower i need runoff or all kinds of problems pop up.
Click to expand...
Thank you!
 
R

retiredcarp

Member
thumper60 said:
Been using promix hp 40 plus yrs it takes 120oz to get 10 percent runoff in a 3 gal pot,Would like to see a pic of the autos if it takes a week to dry back plant is to small for the pot. my photo plants in 3 gal pots are bone dry in 24 hrs. Once plants are in flower i need runoff or all kinds of problems pop up.
Click to expand...
Thank you!
 
R

retiredcarp

Member
chuckeye said:
Geez, it takes what it takes. I'm on my 3rd (?) version of bags, they are all slightly different and do not hold exactly 3 gallons.

Measure your water and keep adding until you get the run off you want. Done.

I would be looking at what ppm's are you feeding ? Salt buildup at 4 weeks is overfeeding...

ProMix HP has been my go to medium for years and I don't water to run off, at least not on purpose ;)

AN, Mega Crop and GH Maxi series. All work as well without run off or flushing.

But I am careful to read my plants and not increase their feed until they ask for it.

Long story, short. The bottom fan leaves will start to yellow. Up the feed by .5g/4L.

Burnt tips, back off.

When I was using AN M/G/B anything over 1000 ppm was too much...

Cheers
Click to expand...
Thank you!
 
chuckeye

chuckeye

Well-Known Member
thumper60 said:
Been using promix hp 40 plus yrs it takes 120oz to get 10 percent runoff in a 3 gal pot,Would like to see a pic of the autos if it takes a week to dry back plant is to small for the pot. my photo plants in 3 gal pots are bone dry in 24 hrs. Once plants are in flower i need runoff or all kinds of problems pop up.
Click to expand...
I've found it depends on the size of the pot. My original 3 gallon bags are 11" W x 9" H, 4L virtually no run off.

New bags 9" W x 11" H, ~10 % run off with the same amount of water !

Cheers
 
Dorian2

Dorian2

Well-Known Member
I've used Promix and this year was the first grow without much of an issue. Used the same technique for runoff and nutrient amount as has already been mentioned. Runoff every feed and waaay less nutrients than is typically suggested. I believe I used less than half the amount suggested by the manufacturer. Worded out to be about 500 PPM all told. Worked like a charm.

Good luck with your grow.
 
W

waterproof808

Well-Known Member
retiredcarp said:
I use promix HP straight out of the bail also, I use nutes at every watering and was told by AN and lots of other growers that if you dont nute to a 10-15% runoff the soil gets salinated and causes lots of problems.
Click to expand...
Thats not totally true. Salt build up happens when your medium gets too dry and salts fall out of solution and crystallize in your medium. The more you let your medium dry back, the more your EC will spike and the more run-off you will need to flush out the excess.

Just think, if you had 1 cup of solution that was 1000ppm and evaporated half the water off of it, your PPM would now be twice as a high since you have the same amount of salt but half the water.

I feed 3x a day at 1.5EC and get minimal run-off, by "AN and lots of other growers" logic, my plants should be burnt to a crisp by end of flower, yet they are still green and healthy.
 
OldMedUser

OldMedUser

Well-Known Member
waterproof808 said:
Thats not totally true. Salt build up happens when your medium gets too dry and salts fall out of solution and crystallize in your medium. The more you let your medium dry back, the more your EC will spike and the more run-off you will need to flush out the excess.
Click to expand...
That's not totally true.

My plants are often drying out and drooping badly and of course any salts are crystallizing but immediately go back into sol'n when water hits them.

That does not create a buildup unless they get overfed often.
 
R

RCJR

Active Member
waterproof808 said:
Thats not totally true. Salt build up happens when your medium gets too dry and salts fall out of solution and crystallize in your medium. The more you let your medium dry back, the more your EC will spike and the more run-off you will need to flush out the excess.

Just think, if you had 1 cup of solution that was 1000ppm and evaporated half the water off of it, your PPM would now be twice as a high since you have the same amount of salt but half the water.

I feed 3x a day at 1.5EC and get minimal run-off, by "AN and lots of other growers" logic, my plants should be burnt to a crisp by end of flower, yet they are still green and healthy.
Click to expand...
What size pots are you in?
 
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