155202502

I have a batch of soil mixed up ready for when my seedlings need transplanting.

It consists of:

7 parts (64%) Miracle Grow Organic Soil
3 parts (27%) Vermiculite
1 part (9%) Peat Moss

I have been testing the pH by running water through it and sampling the first bit of runoff. Using water with a pH of ~7.2 the runoff is off the scale acidic (less than 6.0). I am using one of the chemical color test kits to check the pH, the kit I have is supposed to be accurate between 6.0 and 7.8. The cheap stick type soil pH tester that I usually don't trust has indicated a pH around 5.8.

I think the soil is way too acidic. I am thinking about buying some lime to add to the soil to bring the pH up.

Questions:
Am I correct in thinking I need to add some lime to the mix or should I consider something else?

Does my mix appear to have enough vermiculite and peat to make it drain properly?

Any other suggestions?

buzzmobile

Lime will bring the pH up. Hydrated lime will raise it quickly dolomitic lime works slowly over the course of weeks. Before you do that it would be a good idea to get more accurate pH reading.

Perlite would be a better choice over the vermiculite. Vermiculite holds too much moisture, perlite improves drainage and holds moisture at the same time.

155202502

I made a huge mistake in my post. I did use perlite in my mix and NOT vermiculite. At one time I had bought both but returned the vermiculite. For some reason I had the wrong name stuck in my head when I wrote my post.

It should of read:

7 parts (64%) Miracle Grow Organic Soil
3 parts (27%) Perlite
1 part (9%) Peat Moss

buzzmobile

That looks good. If anything a little more perlite could be added. Try the fistful of soil compression test. Take a fistful of your moist mix and squeeze it firmly in your hand. Slowly open your hand and observe what the soil mix does. If it crumbles, your good to go. If it sticks in a ball you still ahve some work to do.

155202502

I did have some work to do. I did the fist test and it didn't crumble much at all.

Now my mix consist of:
7 parts ( 54% ) Miracle Grow Organic Soil
5 Parts ( 38.4% ) Perlite
1 part ( 7.6% ) Peat Moss

I then added 1 tbsp per gallon of Pennington Fast Acting Lime.

I will test over the next few days to see how the pH changes and if it breaks up easier. I am glad I am doing this now. I think I will be transplanting into this soil in about two weeks.

shrubz

I check the soil itself for its ph, not the run off it istn as accurate

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155202502

After adding the extra perlite the soil still did not drain as well as I expected it to and did only a little better in the fist/crumble test.

I also saw no change in the pH of the runoff water after adding the 1 Tbsp /gallon of lime. I didn't expect it to change instantly so I watered the soil and waited a few days before testing the runoff pH again.

Now I have added another 1 Tbsp / gallon of lime bringing the total to 2 Tbsp /g and added another part perlite.

7 parts ( 50% ) Miracle Grow Organic Soil
6 Parts ( 42.8% ) Perlite
1 part ( 7.2% ) Peat Moss

BTW: these figures are by volume not by weight. That seems like a way too much perlite but it does not look any different than the soil I see in the grow journals.

I know I needed something more accurate than an aquarium chemical pH kit so Monday morning I ordered a Milwaukee SM802 pH/ED/TDS meter. Actually I spent the extra money to get the AG900 kit. It is the SM802 in an "agricultural kit". It comes with a hard storage case and an extra instruction book that is supposed to detail how to use the meter to test soil and fertilizers. I hope there is $30 worth of info in that agricultural instruction book.

I hope to get the meter early next week. Then I can get a real reading of my soil and water pH.

tripps

I have the Milwaukee SM100, ph meter, I think you made` a good choice, I've gone as much as 3 months between calibrations, it's never been off by more than .1 . Yes, that does seem like an awful lot of perlite. I dunno, not a soil guy.

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buzzmobile

I have used MiracleGro soil in a couple of instances and I found it to be very heavy. I added plenty of perlite before I was satisfied with the consistency. Well draining soil is very important.

johnny-0

When adding hydrated lime-remember, if there has been a lock-out there is going to be a lot of nutes released by getting to the proper PH.Go slow on adding new fert.s till plants have a chance to use the ones already in the soil.