rkennedy1945
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Soil PH

I have been growing tomatoes and peppers in 22” and 18” ID for several years. I have been trying to lower the PH with plants about 18” high. Current PH is 7.5. I understand tomatoes and peppers like PH around 6.5. I have added peat, ammonium sulfate, 30% sulfur and now 4 tank spoons of vinger and I can honestly say very little change. Maybe down to 7.2. I was adding 1/4 cup of sulfur. How much and how long should I expect it to take to get the ph in the 6.5 range? Thanks

imafan26
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What is the base of your soil? If your soil has a lot of compost or calcium then it is harder to lower the pH. Peat moss that is not limed has a pH of about 3. Peat that is limed will have a pH or about 6.0 Add sulfur for acidifying soil takes about 2 lbs or about 2 3/4 cup - 4 cups of elemental sulfur per plant to reduce the pH by 1 pt. It takes about 6 months to do this because ultimately it is the soil biota that you are changing they are the ones that will actually make the soil pH more acidic.

If you are growing in pots just grow in Peat moss and perlite 50/50 mix with an acidic fertilizer like tomato or citrus food which contains sulfur. The peat moss will have a pH of around 6.0. The perlite is fairly neutral. For an 18 gallon pot, approx 20 inch pot, You will need about 2 cups of citrus food, mine is 6-4-6 with slow nitrogen, or about the same of tomato food which is 9-12-12. Mix it into the soil as a starter fertilizer. If you use higher number fertilizer you will have to decrease the amount. After the tomatoes flower give an additional 1 tablespoon of fertilizer per month until the tomatoes die. If you want to put organic in the pot, the only thing that has not harmed the plants for me is a couple of handfuls of vermicast. Compost holds too much water and is too alkaline although it does buffer the pH. Manures will just kill the plants if they grow at all.

I don't do organics in pots. The soil organism population in pots are too small and cannot support heavy feeders in pots. My yields are better with conventional fertilizer and I don't like to have to make compost tea or fish emulsion every week to feed the plants. That is definitely not self sustaining if it requires constant inputs to get poorer results than conventional.

PaulF
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If I understand it, your tomatoes and peppers are being grown in containers, is this correct? If so, my recommendation is to use soilless mix as the medium. If you are putting actual soil in the pots, it has a tendency to get very hard and water will not permeate very well. This will take the work and expense out of trying to find a balance.

My garden soil has a naturally high pH and it is a struggle to keep it in the upper seven range. I soil test every other year and need to add sulphur in various forms to achieve anything under 8.0 pH. Soils will tend to return to their natural state if not amended. Container gardening with soilless mix is easier and results are better than using regular soils.

As with almost all soilless mixes the pH will be in the range for good growing. Be sure to have drainage holes and then replenish the nutrients every ten days or so by watering with a water soluble fertilizer. Higher nitrogen formula at first but as soon as a bud shows switch to the fertilizer known as "bloom booster" or its equivalent. Higher P and K will help with blooming and fruiting.

rkennedy1945
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The base of my potting soil is a good grade potting soil and is about 3 years old and has been fertilized every year. Current PH avg about 7.5 and I would like to get it around 6.5. Tomatoes are starting to bloom and 15-18” high in cages and staked. There is little to no mulching / mixing that I can do currently. I will need to try to lower the ph with solvable ingredients such As vinger or sulfur or something in water. Any wise suggestions?

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applestar
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Try putting earthworms in each pot and inoculating with some kind of myco. They will tend to try to neutralize pH in the soil.

Fungal microbes tend to create more acidic environment. You can buy mycorrhizae specially intended for soil amendment, for purely, but my vague and generalized method (which is not intended for immediate results) is to mix in mushroom compost, rotten wood (inspect for bugs first), home made compost (ingredients included citrus scraps and coffee grounds, etc.) which also had mushroom scraps, etc added at some point and had running mycelia growing in it at some point, as well as to blend in premium potting mix with added mycos.

I also water with actively aerated compost tea, leftover juices, tea, coffee, etc. Yogurt, etc. whey and milk mixed in unchlorinated/dechlorinated water can promote lactobacilli population which also prefers acidic environment. Chlorinated water will kill or diminish microbial activity.

imafan26
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I have had problems rebalancing potting soil for reuse in pots. Last year I had to reuse potting soil because it was so hard to find it. It disappeared off the store shelves in days.

It took me a while to figure out how much fertilizer I had to use. I had to use the same amount of fertilizer as the original starter mix because nearly all of the nutrients, especially nitrogen was depleted. I also had problems with disease,soil borne pests and decaying roots in the pot. The decaying roots were a problem even after sifting it out it there would still be some left. The decaying roots competed for nutrients with the plants.

I ended up having to use half old soil and adding at least half new soil mix. Unfortunately, since I can't sterilize the soil mix, I am now paying for the soil pest and disease problems that got out of hand.

Before, I had always put the old soil into the yard or garden. In small amounts it won't affect the garden. If the soil is not reused too often pest and disease problems don't build up because it could not be sterilized.

Your plants are already growing, so it is hard to change the pH of the media in time for the plants that you do have.

If you have good organic matter in the pots, you could still get a decent crop. Organic matter buffers soil pH. That is why even though aerated compost is more alkaline it behaves more neutrally because of the buffering effect. PH will determine what nutrients are available to the plants. The easiest way around that now is not to worry about the pH but to deliver nutrients to the plants in sufficient quantity. For, that I would do water soluble feedings weekly. Tomatoes do like to be slightly acidic but will tolerate up a pH up to 7.5. If it were a truly acidic plant like blueberries, it would not.

After your plants are done, I would remix your potting mix, sterilize if you can and rejuvenate the soil by adding new components or recycle the old mix somewhere else and start new.



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