DIY Supersoil PH too high?

[Dabuddha]

Hey guys, First grow first post longtime toker
Five weeks ago I started my own supersoil with intent to use in a 3x3x6 indoor autoflower grow room. Room consists of 1x MarsHydro TS1000 LED 2x 110w 2700k fluros 1x 190cfm exhaust and passive inlet 2x oscillating fans 3x autoflowers planted in 3gal fabric pots.

Soil consists of
30l peat moss
10l bagged chicken manure
10l mushroom compost
Perlite
Vermiculite
Blood and bone
Kelp meal
Epsom salt
Langbeinite
Bokashi mix
It has been cooking in a 60L black bin with lid and turned every few days for over a month. Tested the soil PH today and its 8-8.5. Should I lower the PH to 6.5-7 before planting seeds or plant and water with lower PH water? Cheers

 

[Dabuddha]

Coco peat* not peat moss

 

[MIGrampaUSA]

Hey guys, First grow first post longtime toker
Five weeks ago I started my own supersoil with intent to use in a 3x3x6 indoor autoflower grow room. Room consists of 1x MarsHydro TS1000 LED 2x 110w 2700k fluros 1x 190cfm exhaust and passive inlet 2x oscillating fans 3x autoflowers planted in 3gal fabric pots.

Soil consists of
30l peat moss
10l bagged chicken manure
10l mushroom compost
Perlite
Vermiculite
Blood and bone
Kelp meal
Epsom salt
Langbeinite
Bokashi mix
It has been cooking in a 60L black bin with lid and turned every few days for over a month. Tested the soil PH today and its 8-8.5. Should I lower the PH to 6.5-7 before planting seeds or plant and water with lower PH water? Cheers

Absolutely bring the pH down before planting the seeds! I target my soil at 6.5 but usually I have to use dolomite lime to raise it a bit. Here's a picture of a nutrient uptake chart. The right half is for soil grows.

 

[Jimster]

It's a little unusual to have a high Ph like that... I would think it would be a bit on the acidic side. Peat is usually acidic as well so I can't understand where the high Ph is originating. You would want your soil to be a Ph of around 6.5, which seems to be the sweet spot for mixed medium grows. You might need to work a soil acidifier into your mix instead of Ph'd water... it's better to start with a stable Ph instead of trying to keep it in range by Ph manipulation when watering. Ph 'd water will quickly be overwhelmed by the overall Ph of the mix.

 

[MIGrampaUSA]

It's a little unusual to have a high Ph like that... I would think it would be a bit on the acidic side. Peat is usually acidic as well so I can't understand where the high Ph is originating. You would want your soil to be a Ph of around 6.5, which seems to be the sweet spot for mixed medium grows. You might need to work a soil acidifier into your mix instead of Ph'd water... it's better to start with a stable Ph instead of trying to keep it in range by Ph manipulation when watering. Ph 'd water will quickly be overwhelmed by the overall Ph of the mix.

He may have gone a bit heavy on the bone meal. That will raise pH. He also corrected himself. He's using coco peat ... but regardless, his pH still seems very high.

I also feel its much easier to start with a stable pH soil that is 6.5 or very close to that.

 

[JWM2]

How are you testing the ph would be my first question.

 

[MIGrampaUSA]

How are you testing the ph would be my first question.

Local hydro store is usually the best start. Some can do testing right on the spot. Almost all know where reliable testing can be done.

You can also use home test kits but the accuracy of those has been questioned time and time again.

Edit: If you know a local commercial farmer, they would likely know where reliable soil tests can be done.

 

[Dabuddha]

How are you testing the ph would be my first question.

Soil was tested with a Manutec soil test kit

 

[Dabuddha]

He may have gone a bit heavy on the bone meal. That will raise pH. He also corrected himself. He's using coco peat ... but regardless, his pH still seems very high.

I also feel its much easier to start with a stable pH soil that is 6.5 or very close to that.

I sure did go a bit heavy on the blood and bone, will aluminium sulfate work to quickly bring down ph? I plan on planting this week

 

[MIGrampaUSA]

I sure did go a bit heavy on the blood and bone, will aluminium sulfate work to quickly bring down ph? I plan on planting this week

Why not use peat moss? It's acidic in nature, natural, and will act as a buffer too.

 

[Jimster]

The problem might be that the bone meal, depending on it's composition, might outlive the Aluminum tretment. I think Bone Meal takes a while to dissolve and lose it's alkalinity, so any treatments would also need to be long lasting. As much as I hate to sy it, but you might be better off making up a new batch and avoiding the Ph ballet that will probably rear it's ugly head.

 

[MIGrampaUSA]

The problem might be that the bone meal, depending on it's composition, might outlive the Aluminum tretment. I think Bone Meal takes a while to dissolve and lose it's alkalinity, so any treatments would also need to be long lasting. As much as I hate to sy it, but you might be better off making up a new batch and avoiding the Ph ballet that will probably rear it's ugly head.

I feel the same ... by the time you're done you might have a toxic chemical cocktail. I used Fox Farm Happy Frog and course to medium perlite with promix. Then I adjusted pH with Dolomite Lime to 6.5.

 

[Dabuddha]

Thanks for your suggestions. So I ended up taking 25l of my soil and mixing it with 5l of peat moss which lowered the Ph to 6.5-7. Seeds have germinated and sprouted to 1.5inch, one with first jagged leaves

The cotyledon leaves on two seedlings have yellow tips but otherwise look ok. The other seedling still has its helmet on. 20hrs on 4off light schedule