Acidic potting soil home depot

I grow fruit and vegetables organically in my front garden in boarded raised beds. I would love to grow blueberries, but I know they need an acidic soil. How can I create a bed for them without using any peat-based products?
Peat-free soil for acid-loving plants does exist, but you might not be able to get it from every garden centre you visit. The best one I’ve tried is made by Melcourt and is called SylvaGrow ericaceous compost – this is the bee’s knees, although I’d say that about all of this company’s composts. You can get hold of it online and it’s also available from a number of good garden centres: visit for a list of stockists.

A maximum pH of 5.5 makes for ideal growing conditions for blueberries to thrive, so mulching around your blueberry bushes with a thick layer of pine needles will also help keep the soil acidic. I’ve also had good results with blueberries grown in tubs by regularly adding the ends of the coffee pot to the surface of the compost. Blueberries love nitrogen, which coffee grounds are high in, and their acidic nature helps gently to keep the soil at the lower end of the pH scale.

What Is Ericaceous Compost: Information And Plants For Acidic Compost

The term “Ericaceous” refers to a family of plants in the Ericaceae family – heathers and other plants that grow primarily in infertile or acidic growing conditions. But what is ericaceous compost? Read on to learn more.

Ericaceous Compost Info

What is ericaceous compost? In simple terms, it is compost suitable for growing acid-loving plants. Plants for acidic compost (ericaceous plants) include:

  • Rhododendron
  • Camellia
  • Cranberry
  • Blueberry
  • Azalea
  • Gardenia
  • Pieris
  • Hydrangea
  • Viburnum
  • Magnolia
  • Bleeding heart
  • Holly
  • Lupine
  • Juniper
  • Pachysandra
  • Fern
  • Aster
  • Japanese maple

How to Make Compost Acidic

While there’s no ‘one size fits all’ ericaceous compost recipe, as it depends on the current pH of each individual pile, making compost for acid-loving plants is much like making regular compost. However, no lime is added. (Lime serves the opposite purpose; it improves soil alkalinity—not acidity).

Begin your compost pile with a 6- to 8-inch layer of organic matter. To boost the acid content of your compost, use high-acid organic matter such as oak leaves, pine needles or coffee grounds. Although compost eventually reverts to a neutral pH, pine needles help acidify the soil until they decompose.

Measure the surface area of the compost pile, then sprinkle dry garden fertilizer over the pile at a rate of about 1 cup per square foot. Use a fertilizer formulated for acid-loving plants.

Spread a 1- to 2-inch layer of garden soil over the compost pile so the microorganisms in the soil can boost the decomposition process. If you don’t have enough available garden soil, you can use finished compost.

Continue to alternate layers, watering after each layer, until your compost pile reaches a height of about 5 feet.

Making Ericaceous Potting Mix

To make a simple potting mix for ericaceous plants, begin with a base of half peat moss. Mix in 20 percent perlite, 10 percent compost, 10 percent garden soil and 10 percent sand.

If you are concerned about the environmental impacts of using peat moss in your garden, you can use a peat substitute such as coir. Unfortunately, when it comes to substances with a high acid content, there is no suitable substitute for peat.

It is often a challenging task to choose the right compost for your garden, especially when you are a beginner. With such a massive list of options available, knowing which kind is best suited for your flowers or plants can be overwhelming.

In most cases, the key is to consider the preferences of your plants in soil. Even the smallest difference in pH levels and nutrients can affect the suitability and growth of your garden.

In this guide, I’ll show you some basic facts about ericaceous compost, one of the most common options for acidic plants, and how to make it yourself.

What is ericaceous compost?

Ericaceous compost is the most common type that most gardeners often come across. The name is derived from the Ericaceae family, which includes those plants that mainly grow in acidic and infertile soil.

Thus, ericaceous compost is simply a substance which is used to create a favourable living conditions for acid-loving plants, such as rhododendron, camellia, blueberry, cranberry, gardenia, azalea, hydrangea, Pieris, magnolia, viburnum, holly, lupine, bleeding heart, fern, aster, juniper, pachysandra, and Japanese maple.

Why do we need ericaceous compost?

Soil can have different pH levels, ranging from alkaline, neutral to acidic, with each one being suitable for particular plants. If you plant any acid-loving flowers or trees mentioned above in limey or alkaline soil, they will produce yellow leaves due to lime-induced chlorosis. As a result, these plants can’t grow well and eventually die.

The easiest way to acidify your soil is to use ericaceous compost. With a high amount of iron and other nutrients which are insoluble in high-pH soils, this type of compost can help reduce the pH levels over time and create an ideal environment for your plants.

Common ingredients to make ericaceous compost

Here are a few common ingredients that you can mix to make your own ericaceous compost:

a. Oak and beech leaves

These are a good source of essential carbon to make compost. Both beeches and oaks belong to the Fagaceae family whose foliage would acidify the soils when it gets decomposed. These leaves often require approximately two years to turn into mould. To accelerate the process, you can chop them up into small pieces, keep the mixtures moist, or add nitrogen sources such as manure, food scraps, and grass clippings.

b. Pine needles

Pine needles are increasingly becoming a popular option for garden mulch. While red, fresh needles are often used as mulch for the garden bed, newer ones can take more time to decompose. Gray and dingy pine straw bales are not attractive as mulch, but they are ideal for composting.

c. Coffee grounds

Many studies have proved that coffee grounds contain a high level of nitrogen, which can reduce the pH level in soils. By adding them into your ericaceous compost, you can allow pine straw and autumn leaves to break down quickly.

d. Peat moss

When combined with ericaceous plants in the soil, peat moss can improve the acidity in soils and promote healthy development. However, keep in mind that peat is typically a finite resource which takes centuries to grow. This means that it can be costly to make your ericaceous compost with this ingredient.

How to make ericaceous compost

There is no one-size-fits-all recipe for making ericaceous compost, and it mainly depends on the specific requirements of your plants as well as the current pH levels in the soil. However, the standard formula is quite similar to regular compost with some basic ingredients mentioned above.

Firstly, you’ll need a good compost bin. You should begin the compost pile with a layer of organic components in six to eight inches.

To improve the acid content, it is advisable to mix high-acid ingredients such as coffee grounds, pine needles, or oak leaves. Even though compost will eventually revert to a neutral level of pH, the inclusion of pine needles can help acidify the soils until they get decomposed.

Next, measure the entire area of your compost pile and sprinkle dry fertiliser on the pile. The ideal rate is approximately 1 cup for each square foot. Remember to use a fertiliser which is specially created for acid-loving plants.

Spread a layer of soil in your garden over the pile so that the microorganisms can speed up the decomposition process. In case you do not have enough garden soil available, consider using finished compost. Keep alternating layers and watering after every layer till the compost pile reaches 5 feet in height.

Useful tips to use ericaceous compost

Keep in mind that the effects when you combine ericaceous compost with soils in your garden are just temporary, meaning that the compost will lose its acidity over time. Thus, it is necessary to check the pH level frequently to make sure you still deliver the right condition (from 4 to 5 pH).

Maintaining the acidity isn’t hard as you can add acidifying materials such as mulch, leaf mould, bark chippings, and pine needles.

Tap water contains alkaline, so do not combine it with your ericaceous soil or use it to water your acidic plants. Instead, collect rainwater for irrigation purposes to maintain the level of acidity in the soil. If necessary, consider adding vinegar to tap water to mimic rainwater. However, it can be costly and time-consuming.

If the level of pH is too high or your garden is quite large, it’s better to use ericaceous compost in containers or pots. This will reduce the amount of compost you need to use. More importantly, it gives you the freedom to position your plants in suitable areas with shade, an ideal condition for acidic-loving plants to grow.

Make ericaceous compost

Ericaceous plants are plants that like low pH, acidic soils. These plants hate high pH, alkaline soils, so they hate lime.

Which plants are ericaceous? Azalea, Blueberry, Camellia, Calluna, Enkianthus, Gaultheria, Kalmia, Pieris, Rhododendron are some examples.

If you are adding compost to the soil of any of these plants, you want to make sure that your compost is lime free, and has a more acidic, low pH to it.

Two easy ingredients to add to your compost to raise the acidity are pinestraw (although I have to warn you that it is EXTREMELY slow to break down, so only add small amounts at a time and make sure it is broken into as small pieces and you can get it) and coffee grounds.

Did you know that you can get huge amounts of coffee grounds at most local coffee shops? Starbucks in particular will give you large bags for free if you ask for it. Other coffee shops will often give them to you too, because they are often just throwing them into the dumpster anyway.

Coffee grounds are a nitrogen rich ingredient, and pinestraw is a carbon rich ingredient, so they actually balance either other out well in the composter when it comes to breaking down, yet they both increase the acidity at the same time.

Want to know the pH of your soil or compost? Try our electronic soil tester. And if you want to make compost quickly, our top recommended composter is the Spin Bin compost tumbler.

Here’s to making your own ericaceous compost for your acid loving plants! Good luck.

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