How To Lower Soil pH in Potted Plants

Last Updated on April 15, 2024 by Real Men Sow

Knowing how to lower the soil pH of potted plants is essential. It is because many household plants require acidified soil with a low pH to thrive and bloom independently.

We’ve developed a step-by-step guide to help you get started quickly and efficiently.

How To Lower Soil pH in Potted Plants?

You can lower the soil pH of potted plants by using quick-acting substances such as elemental sulfur or sulfur in other forms of acidic fertilizers. To lower pH in alkaline soils, you can also use organic options.

Adding Sulfur

The best way to lower soil pH is to add elemental sulfur in a professional and controlled manner. It is an essential nutrient that not only lowers soil pH but also aids in the growth of plants. It can also stay in the soil for a very long time.

Add 0.1 lbs of elemental sulfur per 10 square feet of soil to increase acidity by 0.5 pH. However, this would take a while to carry into effect. It is why elemental sulfur should be added to the soil in the fall or summer before it can start producing a result. After adding sulfur, checking the soil’s pH for 4 to 6 months is essential. If necessary, you can add more. Follow the instructions on the label.

Adding Iron Sulfate

Iron sulfate is second only to elemental sulfur in providing a quick fix for soil problems. Additionally, it’s easy to find one in a local supermarket or online shop. 

It is essential to follow the instructions strictly as it will allow you to calculate how much material you should use in your soil. This method can cause damage to your plants if there is misuse. However, this sulfate can cause damage to your plants if it is not adequately hydrated.

Mix Compost With Soil

Compost is essential for your plants’ nutrition as it can increase soil pH. For plants with low soil pH, composting should be part of your regular plant care routine. It will allow aeration during its composting process. To make the best compost, continue to stir it in a pile. You can add more browns to your stack, such as wood ashes, than the greens.

Compost is one of the best methods for growing acidic plants. It will reduce the acidity of some of its green parts. Let your compost slowly decompose. Utilize the compost yearly to cover and mix the soil. Your soil will become more acidic as it slowly breaks down.

Make Compost Tea To Lower Soil pH in Potted Plants

You can also use compost to lower the pH of the soil where plants are grown. To make compost tea, fill a 5-gallon bucket with water. It is best to leave the compost tea for at least 24 hours. It is faster to add acidity and nutrients to compost than solid compost.

It will cause the water to evaporate chlorine, which can harm plants. Add 5-10 cups of a compost to the water. Let it dissolve for at least two days.

After two days, strain the compost and put it in a spray bottle. Now you have a foliar spray which you can use to water the plants and spray them regularly. However, the foliar spray works slowly, so you need to keep doing a pH test until you reach the desired level. You may use strained solids to fertilize the organic matter.

Add Leaf Mold With the Soil

It is a much easier method than composting. This leaf mould is best from oak trees and can be easily collected in large quantities each fall.

Next, take a composting container and place the leaves in it. As you find more leaves, keep adding them to the pile. To wet the leaves, pour water into the container and leave them to compost for at least two years.

This pile will soon be full of bacteria, fungi, and worms. It will eventually become soft, brown-coloured, and rich in nutrients and organic matter. To naturally lower the pH of your soil, cover it with this leaf mold.

Add Sphagnum Peat Moss

Peat moss is a natural compound that forms over thousands of years from peat bog peat plants. Peat moss is a soil amendment that lowers soil pH. It also provides essential nutrients for plants.

It is best to add the moss to the soil before potting the plants. To add four to six inches of this moss to the topsoil, use a rake and till it to six inches. It will reduce the soil’s pH for at least two more years.

Although moss can be very effective in lowering soil pH, it is also finite. Many studies now show that peat bogs contribute to the decline of biodiversity. It is best to choose more economically viable options.

Start Using Acidic Fertilizer 

Acidic fertilizer is a quick fix. Depending on the plant’s needs, you may pour it into the soil around low-pH plants. Doing this will raise the pH level immediately, but only briefly.

Potting soil should be acidic if it contains fertilizers that contain ammonium-coated or sulfur-coated Urea as their main ingredient. Ammonium sulfate is the most dangerous of all three, as it has a reputation for causing fertilizer burn. The two other options are safer.

Use Leftover Coffee To Lower Soil pH in Potted Plants

There are three main ways you can use coffee grounds in horticulture. Because the soil’s pH is approximately 6.5, using coffee grounds will not reduce its pH.

However, fresh ground coffee can increase the acidity of your soil. You may use the remaining coffee by diluting it with water at a 50/50 ratio. Pour it onto your soil once a week, and then check the pH level with a pH meter.

For a brief time, coffee can reduce soil pH. It is not a permanent or long-term solution. If this is your preferred method, you will need to continue adding it.

Mix Pine Needle Mulch With the Soil

A pine needle mulch is an excellent option for those who prefer organic over processed foods. Pine needles and pine leaves both increase soil acidity by reducing over time.

Take the pine needles’ needles and any fallen leaves. These can be used as mulch to cover your soil. You can mix them in with the ground up to the top 2-4 inches using a rake. It will ensure that the earth has a deep acidity.

These ingredients are suitable for naturally lowering pH levels in small amounts. A commercial option may be better if you require a more dramatic drop in pH.

Add Aluminum Sulfate To Lower Soil pH in Potted Plants

Aluminium sulfate ranks right up there with elemental when it comes to lower soil pH in potted plants. You can purchase it in powdered form from any manufacturer with good reviews.

To determine how much powder to add to each pot, follow the instructions on the label. You may pour the powder over the soil. Next, work the powder into the potting mixture.

Moisten the soil by pouring water over it. It will activate the chemicals. The first release of aluminium is sulfur, while the pH rises slowly over time depending on temperature and bacteria.

Frequently Asked Questions

Can I use Baking Soda to lower the soil pH in potted plants?

You can use household baking soda (sodium bicarbonate) to lower the soil pH and make acidic potting soil. It is best to make a sodium bicarbonate solution for your soil.

Add one teaspoon of baking soda to one gallon of water. Pour it onto the soil every other day, but not more. You can continue soil testing until you reach the desired pH. Only then can you stop using this mixture.

One of the best things about sodium bicarbonate is its ability to act quickly. You can see a drop in your pH range within two to four hours.

Is it safe to use Vinegar to lower the soil pH in Potted Plants?

Vinegar can lower the soil pH by adding it to water and spraying it on the leaves. The exact ratio of vinegar to the water will depend on how acidic the soil is.

As a guide, mix one cup of vinegar with one-gallon water. You may use it to water plants that thrive in acidic soil. You will need a soil testing kit to monitor the soil’s pH levels. They are inexpensive and easy to find.

Real Men Sow
Real Men Sow

Hello, I’m Pete and I’m currently based in the west of Scotland, in a small place called Rosneath, where I’m exploring my garden adventures. I personally started gardening around 6 years ago and initially, I started out by growing my favorite fruits and berries, such as strawberries, Raspberries & Gooseberries. Since then I’ve added a lot of vegetables and working closely with my neighbor, it’s been a lot of fun.