New Grower Does Soil Buffer The Ph Of Water/Nute-Solution?

[Brother Sweetleaf]

I'm growing 3 Autoflowers-- planted just over 2 weeks ago-- safely outdoors in the wild in 5-gallon pots of soil, and they're hungry as ever for their first "full-strength" feeding of nutes. (Since the soil has naturally-occurring nutrients in it, I fed them mostly-pure water [with a trace amount of SuperThrive added] during the seedling phase. During the past week, I've given a 1/8 dose of some 0-0-1 fish ferts, to encourage root development.)

I am interested in leaf/stem growth right now, so I have a 5-1-1 organic fish fertilizer that I've added to the plant's water... But when I test the nutrient-water, the pH is off the charts in acidity (appearing as orangey-red, lower than 4 on the pH chart).

It seems obviously unwise to feed/water a plant a solution that's so drastically outside the "healthy" pH range... I've been asking for help and opinions on a few different forums (like this one), and most growers are saying "Bro, that's WAY too acidic"... But there HAVE been only a couple of growers who have said that I need not be concerned with the pH of what I add because the plans are grown in soil, and soil naturally buffers the pH so that high-acidity in the water/nute-solution doesn't really matter as it would if the plant were grown in a "soil-less growing-medium" (which does not buffer the pH).

Is this true???

Because these are Autoflowering plants, I'm actually only using 1/2 the dosages of ferts, as is recommended by several sources, so there's no danger of over-fertilizing... That being said, my "little girls" are starving, and need to be fed today, and I could really use some advice here ASAP.

I'd rather avoid spending the money on another bottle of solution if it won't matter anyways because of the buffering ability of my soil.

IS a perfectly pH-balanced water/nutrient-solution necessary if the plant is grown in soil???

DOES soil in fact buffer an excessively acidic nute-solution, making the pH-rating of the solution irrelevant???

Please offer your thoughts, experiences or insights. Thanks!

 

[Dazed]

pH in soil is very important. Too low or high and you will get lock out of some nutrients. You need to be in the 6.2-6.8 range ideally. I would say yes you need to bring that solution up to at least 6.0-6.2. You wouldn't want to do more harm than good bro.

 

[Muddy]

IF, and it's a big IF, the soil is properly balanced and contains sufficient lime, then the pH shouldn't be much of an issue. But even a well balanced soil that is feed continuously with a very acidic feed, will see the soil pH eventually drop. Often by the time any issues are apparent, it may be too late in the grow for any additional lime to be effective since it takes about two weeks minimum to kick in. I think it's a good practice to pH balance your soil before planting and then maintain feeds at the proper level, in the 6.3 - 6.5 range.

Also, I would suggest using different nutrients than the fish mixes. While they are very effective, they are also critter magnets. Nothing like the smell of fish to attract a skunk or raccoon to your grow.

 

[Dazed]

IF, and it's a big IF, the soil is properly balanced and contains sufficient lime, then the pH shouldn't be much of an issue. But even a well balanced soil that is feed continuously with a very acidic feed, will see the soil pH eventually drop. Often by the time any issues are apparent, it may be too late in the grow for any additional lime to be effective since it takes about two weeks minimum to kick in. I think it's a good practice to pH balance your soil before planting and then maintain feeds at the proper level, in the 6.3 - 6.5 range.

Also, I would suggest using different nutrients than the fish mixes. While they are very effective, they are also critter magnets. Nothing like the smell of fish to attract a skunk or raccoon to your grow.

Hey Muddy, wouldn't the huge swing in pH back and forth really stress the plant out? I know my soil is always more acidic after I water and slowly goes back up again as it drys.

 

[Brother Sweetleaf]

pH in soil is very important... I would say yes you need to bring that solution up to at least 6.0-6.2....

Thanks for your answer, and Yes, I agree! The pH in soil is very important. But my question is in regards to the pH of the WATER/NUTE-SOLUTION I'm adding, not the soil itself. Again, I'm told by a couple of sources that the soil naturally buffers the pH from the water/nute-solution, so then the soil's pH is (and will remain) different than the pH of the water. I'm wondering if soil DOES in fact buffer the pH, and if the pH or the water/nute-solution is in fact irrelevant when using soil.

IF... the soil is properly balanced... the pH shouldn't be much of an issue. But even a well balanced soil... will see the soil pH eventually drop. ...It takes about two weeks minimum (for lime) to kick in. I think it's a good practice to pH balance your soil before planting and then maintain feeds at the proper level, in the 6.3 - 6.5 range.

Also, I would suggest using different nutrients than the fish mixes.. Nothing like the smell of fish to attract a skunk or raccoon to your grow.

Thanks for all the helpful info! My soil is/has been properly balanced at about 6.3. It is good to know that the soil will eventually drop it's pH after several feedings of acidic nute-solution, so thanks again for your answer. Thanks also for the advice regarding fish-mixes being a critter magnet. However, I have my plant pots protected by chicken-wire that I barbed at the top, specifically to ward off deer, skunk, and other critters.

Hey Muddy, wouldn't the huge swing in pH back and forth really stress the plant out? I know my soil is always more acidic after I water and slowly goes back up again as it drys.

Great question, DazedandSuperConfused. Thanks for helping to unravel this mystery...

It appears that I'm still curious for an answer though... I understand now that the soil's pH will eventually drop when it's repeatedly watered with a very highly acidic solution...

So then does this mean that the soil DOES in fact buffer the pH, and therefore it IS in fact OK to feed my plants with a nute-solution that's, like, 4 on the chart???

 

[Dazed]

No problem buddy, it's hard to give an exact answer. All I know is I personally wouldn't water with something that low, if it was 5.5 or so and I was totally desperate and just HAD to feed that day I would maybe risk it, but 4 is super super low man, very acidic and could have an adverse effect on your root system-I would guess roots can burn just like leaves can, and that would not be good at all.

It's your call bro, but like Muddy said, even in a well balanced soil with added lime, continous feedings of low pH will eventually bring your soil down, and you're on the boarderline already at 6.3.

Sorry I can't be more help, maybe someone who has experience of low pH feed could help you out.

Good luck, let us know what you decide bud, would be cool to see a journal and some pics of your ladies

Dazed..

 

[Muddy]

Hey Muddy, wouldn't the huge swing in pH back and forth really stress the plant out? I know my soil is always more acidic after I water and slowly goes back up again as it drys.

That's actually a good thing and pretty normal. Cycling through the pH range allows for maximum uptake as different nutrients are most available at different pHs. In my soil less medium I shoot for 6.3 the day after feeding, which slowly rises to about 6.6 as the soil dries out.

 

[Dazed]

That completely makes sense! But wouldn't a big swing be bad, or does it not really work like that?

 

[Muddy]

I've never seen that to be the case. A well buffered soil won't have dramatic swings unless you feed with a very high or low pH.

 

[Brother Sweetleaf]

Thanks for continuing the conversation.

I've spoken to a couple owner/managers of different hydroponic shops/garden-centers in my area, and both seem to think that it'd be OK for me to water my plants-- outdoors in 5-gallon pots of soil-- with a nutrient solution that's rating 4.0 acidity on the pH scale. One store-manager/grower believes that a highly acidic solution WOULD make a difference if the plants were going to be potted for several months of the year, but that since these will be harvested in 7 or 8 weeks, the plants would be fine (since there isn't enough time for the acidic water to drastically alter the soil's pH). He did go on to suggest adding a tablespoon of lime to the surface of the soil before watering, in about 2 more weeks, just to raise the soil's pH a bit from any drop that it did take in the previous weeks.

The nearest store I could get organic pH-up is quite a distance away, is a bit pricey, and-- most importantly-- may be completely unnecessary... I'm thinking of just going on out and feeding them this 4.0 solution of 1/2-strength ferts anyways, and monitoring/recording what happens.

Does anyone else believe that this should be OK??? I'm using pH-balanced soil, as Muddy suggested, albeit without lime.