CalMag seedling dosing question

Bubba's girl

Bubba's girl

Well-Known Member
My seedlings are showings signs of needing more calmag. I normally start out really light with nutes at this stage, but am wondering if it's safe to give them say 5ml/gal at 3-4 weeks old? Already gave them 2ml/gal on the last feed and it wasn't enough. Using RO water. Thanks in advance.
 
Bubba's girl

Bubba's girl

Well-Known Member
bobtokes said:
they shouldn't need calmag at that stage 3/4 weeks, surely
Click to expand...
Actually, just checked my calender, the seeds were started 35 days ago, but were slow to germinate, so I would call it a good 4 weeks in. 5 ml/gallon sound safe to you? With RO water.

They are in 1 gallons promix (40% perlite added), transplanted 1 week ago from beer cups. Strains are from Karma genetics, Headbanger, Karma's OG, and White OG.
 
Bubba's girl

Bubba's girl

Well-Known Member
In the 2nd and 3rd pic that is just some dirt on some leaves from when I transplanted. I think they would have liked to have been transplanted about week or two before I actually did.
 
S

SSHZ

Well-Known Member
By using a r.o. device, you are stripping all the ca and mg that is most likely already in your water. I would always add 5ml per gallon the first few weeks to replace what's being taken out, and then go to 10ml for the duration until 2 weeks before chopping.

Since you are already further along, go to 10ml from now on........I use Botanicare Cal/Mag, by using others you may have to adjust it a bit.
 
coreywebster

coreywebster

Well-Known Member
Don't think its either cal or mag deficiency but you should add it regardless because of the RO water and it usually contains iron and other micro elements which will help the uptake of N amongst other things. You sure might wana try upping the ph a few points to above 6.5, (assuming promix is a soil)
 
Bubba's girl

Bubba's girl

Well-Known Member
coreywebster said:
Don't think its either cal or mag deficiency but you should add it regardless because of the RO water and it usually contains iron and other micro elements which will help the uptake of N amongst other things. You sure might wana try upping the ph a few points to above 6.5, (assuming promix is a soil)
Click to expand...

Promix is a "soiless" soil mix. It doesn't have any significant amount of nutrients. I think it has some sort of ph buffering if I remember correctly (and I often don't).
 
coreywebster

coreywebster

Well-Known Member
Bubba's girl said:
Promix is a "soiless" soil mix. It doesn't have any significant amount of nutrients. I think it has some sort of ph buffering if I remember correctly (and I often don't).
Click to expand...
Forget what I said about going up in PH, Just get some iron in there by way of cal mag or a micro formula

Here's an extract from the promix site

In conclusion, there are several growing practices that are used in classic hydroponics that should not be used for soilless media. First, it is not necessary to use purified water (i.e. reverse osmosis). Secondly, while it may seem wasteful, always leach plants when watering. Finally, monitor soilless medium pH, not water pH.
 
S

SSHZ

Well-Known Member
I've been growing in Pro-mix for over 20 and I tend to disagree with the company's statements above.

1. It is not necessary to use purified water, but everyone's water is different and some should not be used (like mine). If the ppm of your water is over 250-300 to begin with, do not use it!

2. I don't leach, I NEVER have. Use a good quality fertilizer, don't over apply it and watch your plants carefully to adjust the ppm when necessary, and you'll be absolutely fine. A good flush at the end- at least 10-12 days is helpful.

3. And regarding the pH, ALWAYS 6.3-6.5 going in, and you'll always be in a good range.

What they forgot to say is, always add more lime and perlite. The lime dose they put in doesn't last long enough for an entire crop, and the perlite addition will help with the compaction that often happens around the roots.
 
Last edited:
Bubba's girl

Bubba's girl

Well-Known Member
SSHZ said:
I've been growing in Pro-mix for over 20 and I tend to disagree with the company's statements above.

1. It is not necessary to use purified water, but everyone's water is different and some should not be used (like mine). If the ppm of your water is over 250-300 to begin with, do not use it!

2. I don't leach, I NEVER have. Use a good quality fertilizer, don't over apply it and watch your plants carefully to adjust the ppm when necessary, and you'll be absolutely fine. A good flush at the end- at least 10-12 days is helpful.

3. And regarding the pH, ALWAYS 6.3-6.5 going in, and you'll always be in a good range.

What they forgot to say is, always add more lime and perlite. The lime dose they put in doesn't last long enough for an entire crop, and the perlite addition will help with the compaction that often happens around the roots.
Click to expand...

1. Yeah the tap water here is between 400-500 ppm so I use RO water.

2. Yeah I find with Promix, if you leach, it takes forever to dry out (despite added perlite), and the plants don't like it. I do run a lot of RO water to flush them the last 2 weeks though.

3. I've general aimed for 6.0-6.2, but I will take your advice and raise my ph a bit.

How much dolomite lime would you recommend adding? I've never used it before. I can add it on my next and final transplant. This recent transplant I went 2 parts perlite to 3 parts Promix HP.

Thank you for the help. I do have a few grows done in the past, but I'm kinda rusty now, just like my plants bottom leaves.
 
S

SSHZ

Well-Known Member
I work with bales as I have a lot of plants....so 3 3/4 cups dolomitic lime per 3.8 cu. ft. Bale. I then add a big bag of perlite and mix it for a while with a large snow shovel. Look at my grows, the numbers I am telling you are tried and true.
 
daloudpack

daloudpack

Well-Known Member
Doesn't look like cal deficiency to me and with ur leaf tips pointing down I'd say N toxicity because calmag has N in it... If ur not cutting back on N with ur nutes to make up for it u can easily lock urself out...
 
daloudpack

daloudpack

Well-Known Member
Could be over watering also how much how often are u watering ...I find in the seedling stage and even veg itts best to let ur soil get really dry...are u watering by pot weight.? If not start waiting to water till u pick up ur pot and its really light
 
S

SSHZ

Well-Known Member
Promix does best when you don't let it dry up all the way......I would just make sure the top 3 inches of soil is dry, then water....
 
daloudpack

daloudpack

Well-Known Member
Take ur word for it cuzz I don't use promix ....I use fertilome ultimate its the shit don't need to add anything in other then ur base nutes after a few weeks.... Never have to pH and I use plain tap water (mine is around 400 ppm) I never had a problem.
 
daloudpack

daloudpack

Well-Known Member
But I will say I don't see how promix doesn't like running dry when letting ur roots chase ur water down to the bottom of the pot and that increases root health and mass.....which in turn increases growth and nutrient uptake.... U can't just leave ur roots in moist soil they will have no reason to grow
 
You must log in or register to reply here.
Top