Urgent - Soil too acidic...

[PersonalSmoke]

Right now I have 15 seedlings, and all of them are beginning to go down hill. I'm 99.9% sure that this is pH problem.

My soil consists OF 2/3 cheap potting soil (which is 10:10:10), and 1/3 perlite. It says on the bag for the potting soil that peat moss is used, so when I was mixing the soil I added 1 tablespoon of dolamite lime per square foot of soil - apparently this was not enough.

I left a big of the soil in a cup overnight mixed with some water thhat was pH adjusted to 7.0, and in the morning the mix had a pH of 6.5. I had been watering with water that itself was adjusted to 6.4-6.5, so I believe that is where the problems began.

So my question is: what's the best way to bring up my soil's pH? I thought of adding lime to the water, but I'm not sure if this is the correct thing to do, and I'm sick of making guesses and messing up my plants. I'm just not sure how much to add. What should the pH of the water be adjusted to when I feed my plants?

Sorry for the noob question, and thanks for anyone who helps.

 

[HeadyPete]

PH Up from the hydro store. Your water/ferts need to be at 7.3 to get your soil to 6.8.

I wonder if your 10-10-10 soil is too hot for your seedlings. Flush them out thoroughly with plain 7.0 water.

What are the symptoms? A little more detail than "going downhill" would be helpful.

 

[Lune TNS]

Thanks for the quick response, I really do appreciate it. I'm going right now to flush them.

The seedlings are wilting and getting rusty spots on the leaves. I'm going to snap some pics right this moment.

Is there any way to add more dol lime to the mix to stabalize things?

 

[HeadyPete]

Dolomite breaks down much too slow to help now. Usually it needs 2 weeks or more of "cooking" time in your mix before you even use it.

Wilting and spots sound like two different problems. The spots are most likely calcium deficiency caused by the lockout from your low ph. Are the leaves fading in color, while the veins remain dark green? This would be magnesium def. These issues are not life threatening at the moment. Fixing the ph will fix these issues, as long as you are giving sufficient amounts of these nutrients. Some strains like a lot of cal and mag. The old leaves won't repair, but watch new growth for improvement.

The wilting, however, is life threatening. This can happen from overwatering, poor drainage, but I think you have the beginnings of fert burn happening. 10-10-10 is way high for seedlings. Seedlings start in peat pellets, coco plugs, plain soil, etc with maybe 1/4 strength bloom formula just once at beginning (Phosphorus promotes good root growth). They don't get fed at least for a week or two. When the chem fertilizer salts in the soil are higher than salts in the plant, moisture travels from the plant, to the soil, and they wilt. It looks like underwatering and technically it is because the plant can't get the water in the soil.

If It were me, I'd transplant them asap into plain potting soil, no ferts at all, and keep flushing with ph adjusted plain water till they look better. Let them almost dry out between flushings. Lime in your soil mix will always help.

The pix will help sort some things out.

What's with the different user names?

 

[Blackvelvet]

My soil consists OF 2/3 cheap potting soil (which is 10:10:10), and 1/3 perlite. It says on the bag for the potting soil that peat moss is used, so when I was mixing the soil I added 1 tablespoon of dolamite lime per square foot of soil - apparently this was not enough.

I left a big of the soil in a cup overnight mixed with some water thhat was pH adjusted to 7.0, and in the morning the mix had a pH of 6.5. I had been watering with water that itself was adjusted to 6.4-6.5, so I believe that is where the problems began.

Don't you mean your soil has the numbers .1-.1-.1?

If your soil mix is peatmoss and perlite, ph 6.5 would be high.

You use distilled water for testing ph. When you tested your soil ph, that is the initial ph. Ph will go higher after sitting for a week wet.

 

[DirtDoctor]

the optimal pH for a peat-based "soil" mix is between 6.2 and 6.4

 

[VirginHarvester]

PH Up from the hydro store. Your water/ferts need to be at 7.3 to get your soil to 6.8.

And if I"m looking for about a 6.5 do I look for a 7.0 from my water/fert mix?

And for my education, tell me how to go about this. I've been using filtered water and mixing light-medium ferts so far. But now I have a girl almost two weeks in bloom. Heck, I'm not even sure when she started exactly so it could be a little longer. Anyway, do I fill a gallon with water and my fert mix then test it and if it's above 7.0-7.3 do I add some PH Down and retest? And if it's below those numbers do I add PH Up retest?

And as long as I'm putting the correct PH water/fert mix into the soil is it unnecessary to check soil runoff PH?

Thanks.

 

[Blackvelvet]

And as long as I'm putting the correct PH water/fert mix into the soil is it unnecessary to check soil runoff PH?

Thanks.

Test runoff just for fun.

Get a 99 cent gallon of distilled water from the grocery store. Water/fert well till runoff. Wait 30 minutes. Apply some distilled water till 1 or 2 ounces of runoff occurs. Catch on a saucer. Test this ph.

 

[HeadyPete]

And if I"m looking for about a 6.5 do I look for a 7.0 from my water/fert mix?

And for my education, tell me how to go about this. I've been using filtered water and mixing light-medium ferts so far. But now I have a girl almost two weeks in bloom. Heck, I'm not even sure when she started exactly so it could be a little longer. Anyway, do I fill a gallon with water and my fert mix then test it and if it's above 7.0-7.3 do I add some PH Down and retest? And if it's below those numbers do I add PH Up retest?

And as long as I'm putting the correct PH water/fert mix into the soil is it unnecessary to check soil runoff PH?

Thanks.

exactly!

Keep testing for awhile until everything is running smooth. You will usually only need to adjust one way, depending on your water source and ph of nutes, as long as these stay the same.

Mix the nutes, stir well, test solution.

Adjust fert ph, water plants, test runoff.

Adjust nute ph if necessary next time. PH changes are best done gradually.

Soil ph changes over time (drops), plus lime raises over time, so testing regularly will help prevent problems before they show up on your plants. After some time testing you will see a clearer picture of your plants ph.