Are Ashes Good for Garden Soil? (Answered)

by Alex Kountry
Updated on

When it comes to gardening, it’s unlikely to see ashes as a useful garden material, especially if you’re new to the field.

It’s common to consider fertilizers and even compost.

Composting, on the other hand, raises a slew of questions. “Should I put ashes in my garden?” is a common composting question.

You may be wondering whether ashes in the garden are beneficial or harmful.

You may also wonder how using wood or charcoal ashes in the garden will affect your garden. Well, dive right in to find out!

Are Ashes Good For Garden Soil?

Are Ashes Good for Garden Soil

Yes, ashes are good for garden soils because they act as fertilizers. However, care should be taken in how and where ashes are placed in the garden.

It’s also worth noting that the source of the ash is important.

Ashes can be obtained from both hard and softwood. Ashes from hardwood trees, such as oak or maple trees, are high in nutrients and minerals.

But, when compared to hardwoods, ashes from softwoods such as pines and firs contain fewer nutrients and minerals.

It is strongly advised that ashes obtained from hardwood be used to ensure optimal plant growth.

Continue reading to learn more amazing facts about using ashes for garden soil.

What Are The Advantages Or Disadvantages?

The use of ashes in the garden is super beneficial, some of its advantages include;

  • Ashes are an excellent source of lime and potassium, both of which are essential nutrients for plant growth. They also provide trace elements that plants require, such as zinc, iron, boron, aluminum, and manganese.
  • Surprisingly, ashes can be used to control pests as well. It contains potassium that causes discomfort in soft-bodied invertebrates.
  • Ashes can be used to raise the pH of the soil for plants that do not grow in acidic soil. This raises the pH of the soil while decreasing its acidity. However, this should not be used in soils with acid-loving plants.

As wonderful as ashes are for gardens, they do have drawbacks. Here are some of the disadvantages of ashes;

  • Ashes especially wood ashes contain heavy metals such as cadmium and lead which are not healthy for both plants and animals. This can be resolved by putting the appropriate amount of ashes in the soil.

It is safer to apply ashes in the soil based on the type of plant. Acid-loving plants would require a lesser amount of ashes because it can lead to increased pH which isn’t good for the plant.

  • Ashes are the major causes of chlorosis which is the loss of the normal green coloration of leaves of plants. Chlorosis is caused by iron deficiency in lime-rich soils, disease, or lack of light.
  • Applying excess ashes can lead to nutrient toxicity and/or nutrient deficiency issues in plants.  

Here is an article I wrote on using potting soil in an aquarium

How Do I Use Ash In My Garden?

  • First, use a soil fertilizer test and the nutrient the plant requires to grow to calculate the suitable amount of ash to apply to your garden. The amount of ash you use is highly dependent on the plant you intend to cultivate.
  • In a year, the maximum amount of ash that should be applied to a garden is about 15-20 pounds with spacing of 1000 square feet. Exceeding this amount will almost certainly harm your plants.
  • How to apply this ash to the soil is also very important. The ash should be applied evenly to the soils of each plant.
  • It is most preferred to apply ashes in moist soil, this is because ash particles are very fine and can easily be blown by the wind. Furthermore, it is best to avoid making applications when it is windy. 

The most preferred time to apply ashes to the soil is during winter when the soil is naturally moist.

  • During spring, ashes can be applied especially in a vegetable garden with a spade or rake.
  • Finally, you should wear protective wears when applying ashes in your garden. This is due to the alkalinity of ash which can potentially pose a health risk to humans. 

Therefore, when working with ashes, be sure to wear appropriate protective clothing such as long pants, gloves, dusk mask, long sleeve shirts, and eye goggles.

This goes a long way to limit exposures that might lead to skin, eye, or respiratory irritation.

Is Wood Ash Good For Vegetable Gardens?

Yes, wood ash is very suitable for vegetable gardens. Wood ash is rich in nutrients such as phosphorus and potassium, these are necessary nutrients for plants.

So it’s a good idea to use wood ash in your vegetable garden.

However, it’s important to know how much wood ash to use and where to apply it. The wood ash should be used directly on the soil or in the soil, whichever you prefer.

It should be spread in about two ounces of ash to every square yard. 

Most vegetables need a pH of 6.5 to 7.0; it’s nothing new that wood ash plays a good role in increasing the pH of the soil.

Wood ash is about half as effective as lime in neutralizing acid.

If your soil is below 6.5 then you need to add some ash to it to increase the pH level.

Wondering how you can know the pH of your soil? You can test your soil’s pH by using a pH test kit.

It’s that easy, pH test kits have been carefully built and designed to provide reliable soil pH readings.

Also check out this article I wrote mixing mulch with potting soil

Do Tomatoes Like Wood Ash?

Yes, Tomatoes do pretty well with wood ash but not in very large quantity though. They require a pH of 5.5-6.8 and wood ash can help them attain it.

Wood ash is a key to improving soil quality for tomatoes. It supplies nutrients to the soil; in addition, it can reduce possible plant diseases as well.

Tomatoes are relatively heavy feeders, but excess fertilizer can reduce fruit quality and cause other problems such fruit spoilage. For good fruit quality, tomatoes need an ample supply of potassium which can be supplied by wood ash.

Do Cucumbers Like Wood Ash?

Yes cucumbers like wood ash, in fact, many vegetables do well with wood ash. This is because they prefer alkaline conditions of pH 6.5 to 7 or greater. 

They also require significant amounts of potassium, which wood ash provides.

The nutrients in wood ash also dissolve better than those in limestone, making them more readily available to the plant.

Wood ash is used to provide potassium for;

  • Asparagus
  • Broccoli
  • Celery
  • Leeks
  • Onions
  • Potatoes
  • Tomatoes
  • Pumpkins
  • Greens
  • Squash

Wood ash can be applied sparingly on celeriac, eggplant, sweet potato, white potato, raspberry, and rhubarb plants.

These plants require pH levels between 5 and 5.8.

Use slightly more ash on plants like beans, Brussels sprout, corn, garlic, pea, and pepper which require a pH of 5.5-6.8.

What Plants Benefit From Fireplace Ashes?

Alkaline-loving plants are those that benefit from fireplace ashes. They need an increased pH and ashes offer them that.

And since ash is alkaline, it can help to reduce the acidity of the soil.

Plants that thrive in fireplace ashes include;

  • Garlic
  • Chives
  • Leeks
  • Lettuces
  • Asparagus
  • Stone-Fruit Trees
  • Tomatoes
  • Pumpkins
  • Greens
  • Squash
  • Apple Tree
  • Fig Treelemon Tree
  • Basil
  • Phlox
  • Sage
  • Strawberry
  • Cactus
  • Lavender
  • Epiphyllum
  • Rose


Ashes are very welcomed in the garden. However, precautions have to be taken when using ashes on plants.

Ashes are used based on the type of plant and the amount of ashes a plant requires.

Generally, vegetables require alkaline-rich soils; this is where ashes play a major role. They help to reduce the acid content in the soil and increase the alkaline level of the soil.

This is however not obtainable for acid-loving plants which require little or no ashes added to their soil.

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About the author

Alex Kountry

Alex Kountry is the founder of HayFarmGuy and has been a backyard farmer for over 10 years. Since then he has decided to write helpful articles that will help you become a better backyard farmer and know what to do. He also loves to play tennis and read books


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