A lower pH level allows certain plants to more effectively absorb nutrients from the soil so they can flourish. When soil pH is too high, it can pose problems for plant health and growth. For many plants, soil that is high in alkalinity makes it harder for plants to drink in nutrients from the soil, which can limit their optimal growth.
Making your soil more acidic can be challenging because water is often alkaline, and limestone within the soil is regularly breaking down, also increasing alkalinity. Fortunately, there are some organic methods that have proven to be very useful in lowering soil pH in gardens. Here are some suggested ways to make the soil more acidic organically.
Test Your Soil
It is essential you analyze your soil to help understand the pH level. You can obtain a simple test kit at your local garden center. This results will help guide you on next steps to amend your soil accordingly.
The pH scale ranges from 0 to 14, with 7.0 being neutral. pH levels that are 0 to 6.9 are acidic, and measurements in the range of 7.1 and 14.0 are more alkaline. The general goal for vegetable gardens is to have a pH of around 6.5, although there are plants whose ideal pH growing environment varies from those parameters.
Amend Your Soil with Well-Decomposed Compost
Add plenty of organic matter each time you plant in your garden. Well-decomposed compost helps lower the pH of garden soil over time. Amending your soil each season with compost, which is rich in organic matter, is by far the best way to make your soil more acidic because it is done gradually and creates the most benefits for plant growth. It also improves the soil structure and adds beneficial micro-organisms into the soil.
Watering your plants with compost tea can also help make the soil more acidic organically. It is also a great way to feed your plants with fast-acting nutrients. Just take a five-gallon bucket of water and let it sit out in the sun for 24 hours to allow any chlorine to release from the water. Dump some well-decomposed compost into the bucket, usually 1-2 cups per gallon of water, and stir it periodically over 48 hours so that it steeps well. Strain the soil from the liquid. Pour the liquid in a sprayer and use as a foliar feed or simply pour it into a watering can and water your garden with it. Work the solids into the soil at the dripline around the plant(s).
Elemental Garden Sulfur
Applying organic, elemental garden sulfur is a safe and efficient way to make the soil more acidic. Sulfur is an essential nutrient that can bolster disease resistance in plants. It is important to follow the instructions on the package when it comes to this nutrient. Although it is beneficial to plants and can lower the pH of your soil dramatically, it can also have adverse effects on your plants if you overdo it.
Use organic mulch in your garden beds. The material will break down over time, helping to make soil more acidic in the process. Mulching with pine needles or oak leaves can provide an acidic boost. Organic mulches are beneficial for many other reasons as well, such as reducing soil erosion, retaining moisture, regulating temperature, and the release of beneficial nutrients into the soil.
Don’t underestimate the power of your morning coffee! Save those coffee grounds and sprinkle them around your garden or add them to your compost pile. As coffee grounds break down, they will also contribute to making your soil more acidic.
Sphagnum Peat Moss
Adding peat moss to your garden soil can also help to lower the pH of your soil gradually. Peat moss is an excellent soil amendment for acid-loving plants and is easy to incorporate into the soil. Simply add two to three inches to the top of the soil and work it into the layers of topsoil underneath.
Peat moss has lowered in its popularity in recent years both for the cost for expansive gardens and the fact that it is not a highly renewable resource. There is also some controversy on what its harvesting process does to contribute to global warming.
Maintaining Your Soil
It can be a constant struggle for gardeners to maintain the correct levels of acidity in garden soil. Test your garden soil periodically to see where it lies on the pH scale and amend accordingly. Another tip is to consider what you are using to water your garden. Ideally, the most sustainable method is to collect natural rainwater in buckets, rain barrels, or watering cans to best imitate nature. Sometimes, water from the garden house can be very hard water with a high pH, which can also impact pH of your garden over time.
14 CommentsLeave a Reply
what product do you make that will amend a 14 sq. ft garden space with a current pH of 7 to bring the pH down to between 4.8 – 5.5 for potato growing, or some sites say to pH of 6 maximum for potato growing?
Hi Gai! We have a post here about growing potatoes https://www.kellogggarden.com/blog/gardening/best-ways-to-plant-potatoes-in-a-garden/ Changing the pH of your soil is usually a task that takes some time. The fastest way for you to bring your pH down would be through the use of sphagnum peat or you can try a compost or fertilizer tea. Iowa State University has some good information here https://hortnews.extension.iastate.edu/1994/4-6-1994/ph.html if you would like to do more research. You could also choose to buy organic soil that has a lower pH and grow your potatoes in containers. That will allow you to quickly get your potatoes going.
Very good info indeed.
But there is some shortcoming!
The use of various media discussed have not been quantified.
(For example: how much tea leaves, coffee grounds should be used in how much soil.)
And if any material is used (for example: tea leaves etc.) for how many days.
Please add these info in the write-up too.
Hi Sayef, when adding coffee grounds to your soil to adjust the acidity spread a thin 1/2 inch layer of grounds over the top of your soil. It is recommended to scratch the coffee grounds into your soil at a depth of 6 to 8 inches. If you’re applying tea leaves as mulch, simply place a 3 to 4 inch layer on top of the soil, try not to let the leaves touch your plants. They will break down and release their nutrients slowly over time, reapplication rates will vary. If you’re using compost tea in a vegetable garden, apply it once every two weeks and if applying to flower beds use once every 3 to 4 weeks. Compost tea should only be applied in the early morning or in the evening after the sun has set as direct sunlight can damage the plants. We hope this helps, happy gardening!
I love the information that you have shared. I am in a dilemma, I have very hard water with low rain levels in Eastern Washington. How can I make the change from alkaline water to more acidic? Could I occasionally add Vinegar to the water to increase the acidity. Almost all of the areas that I tested are at exactly 7 with the exception to one raised bed at 6.5. I grow mostly vegetables and some berries. Can you help me with any ideas that you might have? Thank you in advance. Victoria
The pH range you want for most vegetables 6 – 7 so having a pH level of 7 is good. For some berries, you would want your soil to be more acidic. To change the acidity of your soil it is best to focus on the soil itself. Changing the pH of the water will not change the pH of your soil, not to mention how time-consuming it would be to do it every time you watered. You can try some of the methods mentioned in this article it will take a little time because you want to slowly amend your soil then test and then amend and test again until you have levels where you want them. You can also purchase soil that is specifically created for acid-loving plants.
I have a vege pod garden that I filled with organic garden soil. I live in Las Vegas and we have very hard water..My ph meter does not register anything .what should I add to the soil..I’m assuming it is too alkaline
Hi Sharon! A pH meter is good for testing water pH but if you suspect that your soil pH is not optimal for the plants you want to grow you would need to do a soil test. You can order those online or in some cases get them from a local garden center or plant nursery. You will also want to get some organic fertilizer to replenish the soil’s nutrients as the plants grow. A combination of fast-acting liquid fertilizer and a slow-release granular fertilizer will help you keep your plants growing strong all season long. https://www.kellogggarden.com/products/kellogg/organic-fertilizers/kellogg-garden-organics-fish-and-kelp-fertilizer/ https://www.kellogggarden.com/products/kellogg/organic-fertilizers/tomato-vegetable-herb-fertilizer/
Hi, I have a 30’x6’ raised garden with a variety of vegetables and flowers. They are planted in sections/groups. In each area I’ve tested I get a pH of 7.5-8.0 and a few fall within normal or the pH needed for that vegetable. My question is, what is the best method to amend the garden given its full of a variety of plants? I’ve read in several places that coffee grounds are the best option since I need to apply to direct areas and the grounds should be fresh/unused? Is this true? Thanks!
Hi Robyn! That is a large garden bed. Some people will add dividers in their beds to separate the sections so they can cultivate different growing environments. Coffee grounds are great for adding organic matter to the soil, improving drainage, water retention and aeration in the soil. They can also be good for microbial soil health. However, coffee grounds have not been shown to have a consistent effect on lowering soil pH. Soil pH can be reduced most effectively by adding elemental sulfur or aluminum sulfate. Typically it is best to amend the soil for pH before the beds are planted so you don’t risk burning the plants.
Can I prepare a bunch of soil acidic for my potted plants by using cooked food waste (veg) or fungal conditioned bread or grind rice husk,green gram peel etc If yes how to mix them? In dry /after boil?
Hello Dwarikanath, we don’t recommend putting any of these items directly in the soil of your potted plants but you can create a compost with them and then use your aged compost in your potted plants. Be careful using cooked vegetables in your compost it can attract pests. Here are two articles to read for composting https://www.kellogggarden.com/blog/gardening/get-started-composting/ and https://www.kellogggarden.com/blog/gardening/how-to-compost-in-the-city/
I am trying to get an accurate pH for my potted gardenia I Purchased about three months ago. It was covered with huge beautiful birds and since bringing it home they have all dropped off and I am very sad about that. I think that my pH is at 8 according to my meter and so I would like some advice.
Hi Jane, we’re so sorry about your Gardenia! Soil pH for gardenias should be between 5.0 and 6.5. Adding sulfur, coffee grounds, peat moss, compost, and mulch can all help. However, to save your gardenia quickly you will need to add aluminum sulfate to your plant’s soil. We recommend testing your soil. Here is an article about soil testing options https://www.kellogggarden.com/blog/soil/how-and-when-to-test-your-soil/