Indoor Changing PH with soil grow

[Think]

I have done a few grows in the past but never thought about changing the PH in the water but I wanted to give it a go, I have been reading a little and someone said don't bother if your growing with soil as you can get lock out by doing it but if you was going hydro then you should consider changing the PH ?

 

[Sauce]

Not sure I fully understand the question. But if you are watering soil with say 7.8 or 5.5, thats not a good idea. Soil you want to water with around 6.4-6.8 to allow the plant to be able to update the nutes. Also to keep your soil in check.

As for Hydro you need to be around 5.5-5.8 during veg with the water.

 

[Darth Vapour]

From what I've read the pH of soil will fluctuate as it becomes moist and dries. The best thing would be to take readings of your soil pH before you plant your beans at different moisture levels and see what your workin with . If it's too low, say in the 5s you could add dolomite lime to raise pH and if your going organic you really don't need to pH adjust your water unless it's waaay off. I literally just received my soil pH meter, accurate 8, and it gives me consistent readings of my soil.

I'm aiming for a range between 6.2 - 6.8, currently I'm on the lower end of that range and sprinkled a little lime in a top dress fashion hoping it'll find its way deeper over time to slightly raise my pH

 

[Muddy]

When growing in soil your ideal pH range is in the 6.3 - 6.5 range. In hydro, it's 5.8 - 5.9. If it's out of range then it should be adjusted to bring it into the correct range for best results. Nutrient lockout occurs when the pH is out of range which can prevent the plants from taking up the nutrients properly. This chart shows what nutrients are available at different pH.

 

[turtle360]

From what I've read the pH of soil will fluctuate as it becomes moist and dries. The best thing would be to take readings of your soil pH before you plant your beans at different moisture levels and see what your workin with . If it's too low, say in the 5s you could add dolomite lime to raise pH and if your going organic you really don't need to pH adjust your water unless it's waaay off. I literally just received my soil pH meter, accurate 8, and it gives me consistent readings of my soil.

I'm aiming for a range between 6.2 - 6.8, currently I'm on the lower end of that range and sprinkled a little lime in a top dress fashion hoping it'll find its way deeper over time to slightly raise my pH



eave:

I hear the Accurate 8 is so fat you risk root damage when you stick it into the container.

 

[Darth Vapour]

It's maybe 10mm wide, less than half inch, I try and avoid sticking it directly in the middle of root ball.

That's why it's best to take readings before you plant. I'm growing outdoors and made a big hole so I take readings off to the sides in 3 different spots.

The unit is pretty long too, 12 inches or 30 cm so for small pots I'm not sure how accurate it'll read if your only sticking it in a couple inches.

 

[Muddy]

I hear the Accurate 8 is so fat you risk root damage when you stick it into the container.

It's about 3/8" in diameter with a pointed end so it pushes the roots aside. Any root damage is minimal. I've been using mine for 3 years now and have never had any issues with my plants that might have resulted from using it.

 

[az2000]

sprinkled a little lime in a top dress fashion hoping it'll find its way deeper over time to slightly raise my pH

I've been testing different amounts of dolomite lime in 8 1/2-gal containers. From none to 8 tbsp/gal. It took 10 days before I began to see an effect on pH, a distinct .1-.2 progression from one container to the next. It's been a month and I'm seeing the same progression. I haven't yet seen the 8 tbsp/gal going higher. (Not that I think this would be a sane quantity. Just saying it seemed to have the same effect as 2-3 tbsp/gal and stopped. But, I'm continuing to water the containers to watch the effect.).

I also added 3/4 tsp/gal hydrated lime to the 8th container (along with 2 tbsp/gal dolomite). That had an immediate (but too strong) effect. For example,

1. The no dolomite container started at ph 5.5-5.7 and has remained there.

2. The 1 tbsp/gal dolomite container started at 5.5-5.7 and appears to have topped out at 6.1-6.2.

3. The 2 tbsp/gal dolomite container started at 5.6-5.8 and appears to have topped out at 6.3.

4. The 4 tbsp/gal dolomite container started at 5.9 and appears to have topped out at 6.5.

5. The 8 tbsp/gal dolomite container started at 5.9 and appears to have topped out at 6.7.

6. The 2 tbsp/gal dolomite + 3/4 tsp hydrated started at 7.9 and has seemed to settle at 7.7.

This was a 3-1-1 (scoops) ratio of Pro-Mix HP, Kellog Patio Plus potting mix, Perlite. I've wanted to have the best of both worlds -- soilless and soil. But, it seems to acidify my mix.

Now I'm growing in 4-1 Pro-Mix, Perlite. But, I'm still experimenting. I feel like a hybrid soilless/soil might offer a wider ph range of nutrient availability. It seems like a touch of hydrated lime added to the mix would help. But, just a touch. Like 1/8 tsp/gal.

It's fun to do these tests. I can't believe I didn't do it a long time ago. Much better to do before you actually need to make adjustments.

One thing that confounds my tests is that everyone (including Muddy) says Pro-Mix is around ph 7 out of the bag. Mine (according to the above test, with no lime and no soil added) is about ph 6. I don't know if I got a bad bag. The Kelogg container (no Pro-Mix, no dolomite) is 7.0. Everything about these two measurements seems backwards.

I feel like the most important thing I learned is that I should do a baseline test on every bag before using it.

Anyway, I just wanted to point out that 1) dolomite takes awhile. 2) More doesn't seem to proportionally affect the ph. 3) Hydrated lime seems to be the answer for faster (and more drastic action if necessary). 4) A small (tiny) amount of hydrated lime might be sane for immediate starting adjustment.

I can't say that I've seen a reliable corrolation between runoff as an indication of soil pH and Accurate 8's direct reading of soil pH. I see the same trend/direction between the two. But, usually not the same value. I imagine the meter is more reliable.

There is a "pour thru" method for measuring ph via runoff. I want to try that sometime.

 

[Darth Vapour]

I've been testing different amounts of dolomite lime in 8 1gal containers. From none to 8 tbsp/gal. It took 10 days before I began to see an effect on pH, a distinct .1-.2 progression from one container to the next. It's been a month and I'm seeing the same progression. I haven't yet seen the 8 tbsp/gal going higher. (Not that I think this would be a sane quantity. Just saying it seemed to have the same effect as 2-3 tbsp/gal and stopped. But, I'm continuing to water the containers to watch the effect.).

I also added 3/4 tsp/gal hydrated lime to the 8th container (along with 2 tbsp/gal dolomite). That had an immediate (but too strong) effect. For example,

1. The no dolomite container started at ph 5.5-5.7 and has remained there.

2. The 1 tbsp/gal dolomite container started at 5.5-5.7 and appears to have topped out at 6.1-6.2.

3. The 2 tbsp/gal dolomite container started at 5.6-5.8 and appears to have topped out at 6.3.

4. The 4 tbsp/gal dolomite container started at 5.9 and appears to have topped out at 6.5.

5. The 8 tbsp/gal dolomite container started at 5.9 and appears to have topped out at 6.7.

6. The 2 tbsp/gal dolomite + 3/4 tsp hydrated started at 7.9 and has seemed to settle at 7.7.

This was a 3-1-1 (scoops) ratio of Pro-Mix HP, Kellog Patio Plus potting mix, Perlite. I've wanted to have the best of both worlds -- soilless and soil. But, it seems to acidify my mix.

Now I'm growing in 4-1 Pro-Mix, Perlite. But, I'm still experimenting. I feel like a hybrid soilless/soil might offer a wider ph range of nutrient availability. It seems like a touch of hydrated lime added to the mix would help. But, just a touch. Like 1/8 tsp/gal.

It's fun to do these tests. I can't believe I didn't do it a long time ago. Much better to do before you actually need to make adjustments.

One thing that confounds my tests is that everyone (including Muddy) says Pro-Mix is around ph 7 out of the bag. Mine (according to the above test, with no lime and no soil added) is about ph 6. I don't know if I got a bad bag. The Kelogg container (no Pro-Mix, no dolomite) is 7.0. Everything about these two measurements seems backwards.

I feel like the most important thing I learned is that I should do a baseline test on every bag before using it.

Anyway, I just wanted to point out that 1) dolomite takes awhile. 2) More doesn't seem to proportionally affect the ph. 3) Hydrated lime seems to be the answer for faster (and more drastic action if necessary). 4) A small (tiny) amount of hydrated lime might be sane for immediate starting adjustment.

I can't say that I've seen a reliable corrolation between runoff as an indication of soil pH and Accurate 8's direct reading of soil pH. I see the same trend/direction between the two. But, usually not the same value. I imagine the meter is more reliable.

There is a "pour thru" method for measuring ph via runoff. I want to try that sometime.

Awesome! Thanks for sharing AZ, I didn't check my soil mix initially since I didn't have a meter at the time but I would hazard to guess my ratio is about 6:1 promix hp and cow shit with some kelp meal and glacial rock dust minerals.

Looks like I'll add some dolomite lime since I have it on hand and don't need to raise my pH substantially plus the plants look healthy. Hoping to hit 6.5 (currently @ 6.2)

Great work again dude

 

[az2000]

Looks like I'll add some dolomite lime since I have it on hand and don't need to raise my pH substantially plus the plants look healthy. Hoping to hit 6.5 (currently @ 6.2)

Glad that was useful to you. Just an FYI, I hadn't tested it for about a week. It's been exactly 30 days since I started the test. I wet the containers today, let it soak in. Wet again for runoff. All the readings are exactly the same as a week ago (which I posted above). A couple are .1 different.

It surprises me that the insane 8tbsp/gal container isn't much different than the 2 and 4tbsp. And, that these things haven't continued going up. They hit their maximum affect at 10 days. In fact, they've dropped .2 after 15 days and have been holding steady there.

The one with 2tbsp dolomite and 3/4 tsp hydrated lime dropped too. (But, it's still too high at 7.3).

I think the problem you'll have cultivating dolomite into your top soil is that it may not work its way through the soil. Even if you need only a .3 adjustment, I'd lean toward hydrated lime. Everyone warns against this because it's so strong (and I've read it is phytotoxic, perhaps at strong or repeated doses?). But, I salvaged a plant that had extremely acidic soil using hydrated lime. It seems like a much more predictable and immediate affect. Because it dissolves (or suspends?) in water I believe it flows through all the soil.

If I were you, I'd do 1/5 of a tsp. I'd weigh a tsp, determine the grams. Then weigh 1/10th.

For me, 1tsp hydrated lime (Fertilome Hi-Yield horticultural lime) weighs 2.5g. And, 3/4 tsp / gal (1.875g / gal) raised my ph 2 full points. It's now holding at 1.2 points above the container without hydrated lime (they both have 2tbsp/gal dolomite). If I wanted to raise it just .3, I'd give it about 25-30% of 1.875g/gal. About 0.5g/gal of hydrated lime. Maybe half that across 2 waterings.

When I had my acid problem, I wasn't sure what the cause was. I felt I needed to flush salts. So, did a couple doses where I poured 1/2 gal water containing the hydrated lime, letting it soak for half an hour. Then fed as normal with a gallon of of nutrient water (plant is in 3gal container). That accomplished a modest flush (not 3x the container size, but a lot more than usual). It was scary because the limed water was about ph 11. Flushing that out after 30 minutes neutralized it with nutes that were ph 7'ish (still high, trying to equalize the low soil ph).

I think if a person is cautious and creative hydrated lime is a good choice. I think people are warned off too much. I think this may arise from people confusing it with dolomite and applying it at the Tbsp quantity. I don't think it's any worse than Muddy using 4g of Alum. Sulf. to lower his ph by .6.

If I'm wrong, I hope someone corrects me.