pH dropping

I need to lower my soil pH. It was fine but now it has dropped into the 5's.

I was told I could use Baking Soda to do this.

What dosage per gallon would be appropriate?

You mean RAISE your pH? I'd be cautious of using baking soda -sodium bicarbonate- over a long period of time, due to a possible build up of salts.
However, you can use it to raise your soils pH for now. Just add a TBS to a few gallons of water and mix it well, then test the waters pH.

You don't want to raise the pH too quickly either, so plan on adjusting over a period of about 2 weeks - a few points at a time until your run-off is around 6.5

Dolomite lime or crushed oyster shells, which can be found at a feed store, will balance the pH more steadily. Stable is the key. You dont want to shock the plant with dramatic pH changes!

What has changed to cause the change? I have 7.6 water and changed to red Miracle Grow to "fix" and my plants did not like it. Advice here was adjust water ph before doing any thing else?. Did not work for me I must be in a 'blue' state? Yes baking soda will raise the ph but go slow just like in a fish tank: shock them and you will lose some!

next time you water? just dont lower the PH so low.. it will balance out, if it goes below 5 i would freak but 5.5 is ideal man. If you using a ph probe? be carful because after a couple months those probs get screwy and give off bad readings..

Yes I meant to raise the pH, d'oh!

I read where adding nutes can raise the pH, and I believe that is what is happening. I just flipped the switch 18 days ago and started the bloom nutes. The leaves are starting to yellow and get papery, but around the veins it is still green. I've been using the same probe right along, but I guess I'll get a test kit as well.

Is lime better than the baking soda? Dosage of lime if so?

The dosage of lime depends on the type, i.e. dolomite, which isnt water soluable, or hydrated which is. Hydrated can be used to adjust the water. Start by slowly adding to water until the pH is where you want it. Of course, you'll need a digital tester for that; im not sure a pH probe can do straight water, but it might. Really tho, you need to know the pH of the water to begin with.

Update.

I got 2 pH test kits, a soil kit and a water kit. I tested the water first.

The water is 7.6. This makes sense. The pH meter had been telling me the pH was fine, when I measured it just after watering. (The pH meter instructions call for a wet soil mix). When I use the pH meter when the soil has dried out a bit, I see the pH much lower.

No sense in measuring the soil until I get some distilled water, which has a neutral pH (I'll test it anyway). That should give me a true soil pH level. Will post up as soon as I get the distilled water and run the test.

Not trying to get ahead of myself, but I'm leaning towards the powdered lime if my pH is in fact as low as I think it might be.

What kind of nutes ru using? My water is 7.6 also, but after adding nutes it drops to about 6.5pH. Always check the water after you add nutes and adjust from there.

I'm using Jack's Classic Dynamic Duo. The issue here is that when watering the pH is fine but as it dries the pH drops, because the soil itself has become slightly acidic. I want to get the soil itself right.

IMO, and recent experience, hydrated lime sux. It tends to spike the pH then drop out rather quickly. Dolomite lime is said to stabilize the pH over a longer period, but most ppl mix it in with their soil before planting. Also, oyster shells - available at any feed/bird store - is said to stabilize soil pH over time as well. An added benefit of oyster shell is that its made of calcium which is beneficial to our beloved plants.

I ran a soil test. N, P and K are all fine. pH is 5.5-6. They are 20 days into bloom. Using Jack's Classic Dynamic Duo.

Here's a photo.



Notice the yellowing. I think the pH needs adjusting. Do you all agree?

novice11 said:

I ran a soil test. N, P and K are all fine. pH is 5.5-6. They are 20 days into bloom. Using Jack's Classic Dynamic Duo.

Here's a photo.

View attachment 1745843

Notice the yellowing. I think the pH needs adjusting. Do you all agree?

Click to expand...

Get yourself a decent meter, I'm thinking your soil test kit isn't accurate. If the runoff is truely that low just water with a ph around 7. It'll balance. That is assuming you want your ph about 6.5. The ph doesn't necessarily have anything to do with the yellowing, what medium are you using???

I've got 2 meters, a digital pH and a 3 in 1 (light/wet/pH) that both agree with the test kit. They are growing in Scott's Moisture Advantage soil. I also have 2 pH test kits. The one for water shows my water is 7.6 and the soil test kit shows the soil (mixed with distilled water, not tap) with the 5.5-6 pH. I think the pH is indeed low.

novice11 said:

I'm using Jack's Classic Dynamic Duo. The issue here is that when watering the pH is fine but as it dries the pH drops, because the soil itself has become slightly acidic. I want to get the soil itself right.

Click to expand...

Get the lime, dolomite is preferred. Powdered or pellets, ~$5 for a 40lb bag at Lowes or HD. I would NOT use hydrated unless you are very experienced with it and I doubt that you are.

Jack's is designed to be used with a limed soil as it contains neither Cal or Mag to avoid lockouts.

I have never pHed Jack's and have used it for well over 30 years. With a well limed mix, there is no need.

Wet

I bought the only Dolomite Lime I could find, Espoma Garden Lime. I added 1 TBSP to each pot, mixed it in and added water. Does that sound like a safe dosage? Eash pot is about 1 sq ft.