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Is wood ash good for compost


How to Compost Wood Ashes

Up here in Vermont, the winters are long.

For me, this means months spent curled up by the wood stove with a book and a cat on my lap.

It also means the creation of a lot of ash – which always leads me back to the question of whether or not I can compost ashes.

As it turns out, the answer is yes, with a couple of crucial caveats.

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This article will explore how to use wood ashes in the compost and in your garden, and when it is appropriate to do so.

What You’ll Learn

Benefits of Wood Ash

Wood ash from your fireplace contains a number of nutrients that can be very beneficial to a garden – in the right circumstances.

But never use the ash from charcoal, trash fires, or treated wood, which can contain toxic chemical residue from additives.

Wood ash contains potassium and calcium in considerable quantities, as well as lesser amounts of magnesium and phosphorus, and micronutrients such as copper and zinc.

Due to its high level of calcium, it can increase the pH of soil, making it an ideal natural substitute for lime, an amendment often used to balance soil that is too acidic.

It can be a very useful amendment where acidity is too high for growing most veggies, in a pH range of 6.0 and below.

But you’ll need to be cautious. If the soil is already neutral or alkaline, adding ashes will cause excess alkalinity and add soluble salts, ultimately doing more harm than good.

So how do you know when it makes sense to add ashes to your compost or garden?

Let’s explore.

Test Your Soil

Before adding ashes (or any other amendment, for that matter) to your garden, be sure to get your soil tested!

You can easily request a test through your local agricultural extension office.

You can buy home pH test kits or meters at your local hardware store or online, though I would recommend getting a test from your local extension office at least once.

The results of these tests are more comprehensive and they will tell you a whole lot about your soil, including information about any other nutrient deficiencies.

If you don’t have access to professional testing or a kit, it is possible to DIY a basic test of the pH with just two cups full of soil, some vinegar, and some baking soda.

Pour vinegar into the first cup. If the soil begins to fizz, it is alkaline.

Add some water to moisten the soil in the second cup, then add baking soda. Fizz this time means it is acidic.

This method is not especially accurate, and you won’t be able to determine the exact pH level of your soil this way. It is still a good idea to get a more accurate test when you are able.

In the meantime, however, this simple method should at least give you a general sense of whether the soil is acidic or alkaline.

When to Compost: Timing and Moderation

The key is to add small amounts of cooled ashes to a new or uncooked pile. Because it has such a high pH value, it is important that you don’t add too much to your compost.

According to Olivia Saunders, Extension Field Specialist in Food and Agriculture at the University of New Hampshire Extension, “it should not make up more than 5% of your compost.”

Additionally, once the compost nears maturity, the addition of ash could raise the pH too much, increasing the bioavailability of heavy metals to harmful levels.

How to Compost

Before you start, be sure to suit up with gloves, eye protection, and a mask to avoid any potential irritation to the skin, eyes, or lungs. Also, ensure that the ashes have completely cooled before handling them.

Sprinkle the ash onto your compost pile along with the appropriate ratio of brown and green material.

What does this mean? Add about a quarter inch for each 18-inch section of browns and for every six inches of greens. Be sure to turn the pile each time you add new material.

As a reminder, browns include carbon rich materials such as straw, hay, and dried leaves, while greens are more nitrogen heavy items such as kitchen scraps and fresh grass clippings.

To learn more on the basics of composting, check out this article.

If you have a hot compost pile, add a small amount of ash along with other new materials every month or so while it is active.

If the pile is cold or rarely added to, only add ash in the fall or late summer, allowing time for everything to break down before being used in the garden during the growing season.

You can collect ashes and store them in a covered container through the winter.

Adding It Directly to the Garden

If you have determined via a test that your pH is low – below 6.5 – you can also choose to add ashes directly to the garden to reduce acidity.

Incorporating ashes can also increase the bioavailability of potassium, phosphorus, and various micronutrients, thereby increasing fertility.

A Note of Caution:

Never mix ashes with nitrogen fertilizer, it can cause a reaction that releases ammonia gas. Always wear eye protection, a face mask, and gloves when handling wood ashes.

Spread on calm days to prevent it from blowing around and scattering to unwanted areas – including all over your clothes.

Apply in moderation, lightly dusting a small amount on the garden surface and working it into the soil several inches deep with a fork.

According to Rosie Lerner, Horticulture Specialist at Purdue University, “Acidic soils (pH less than 5.5) will likely be improved by wood ash addition.

Soils that are slightly acidic (pH 6.0 to 6.5) should not be harmed by the application of 20 pounds per 100 square feet annually, if the ash is worked into the soil about six inches or so.”

Be sure to test the soil again the following year. You can reapply if the pH is still too low, but if it has reached 6.5, don’t add any more. If you raise the pH too much, this can deplete the bioavailability of essential nutrients.

Do not apply to acid-loving plants such as blueberries, rhododendrons, or azaleas.

Continue to test your soil every few years and amend as necessary.

Ashes to Dust

While it is never wise to dump a whole bucket on your compost or in the garden beds, used in moderation with careful planning and an understanding of your soil, wood ashes can be repurposed as a useful amendment.

Though my wood stove churns out far more than I can safely use each winter, I am still able to recycle much of it back into my compost.

Have you used wood ashes in your garden? Please share your experience in the comments below!

If you enjoyed this article, you can learn more composting tricks in these guides:

© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Uncredited photos: Shutterstock. With additional writing and editing by Clare Groom and Allison Sidhu.

Improve Your Soil Using Wood Ash

, written by Benedict Vanheems

If you’ve recently had a bonfire, or like to warm yourself in front of a roaring fireplace or wood burner, then you’ll probably have lots of ash. Getting rid of it can be a bit of a nuisance, but it’s also a valuable source of nutrients, which makes it a great resource for the garden.

Read on or watch our video to discover when and where to use it...

Wood Ash Nutrients

Wood ash is naturally high in potassium, which encourages flowering and fruiting. It also contains phosphorous as well as a catalog of micronutrients including manganese, iron, zinc and calcium.

Younger wood, such as twiggy prunings, produces ash with a higher concentration of nutrients than older wood. Similarly, ash from hardwoods like oak, maple and beech contain more nutrients than ashes of softwoods.

Ash from lumpwood charcoal is also good, but avoid using the ash from coal or treated timber, which could harm your soil and plants.

Wood ash can help make compost less acidic

Using Wood Ash in Compost

Wood ash is alkaline, so applying it to compost heaps helps to balance the tendency of compost to be more acidic. It also creates better conditions for composting worms, which will speed up decomposition. Compost that’s less acidic is perfect for mulching around vegetables.

Add wood ash little and often in thin layers. A few handfuls or one shovelful every six inches (15cm) of material is fine.

Using Wood Ash on Soil

Wood ash can play a useful role in correcting overly acidic soil. Most vegetables need a pH of 6.5 to 7.0, so if your soil’s below 6.5 sprinkle wood ash over the surface then rake or fork it in. Test your soil using an inexpensive test kit if you don’t already know its pH. Wood ash is particularly useful if you use lots of cattle manure in your garden, as this type of manure is very acidic.

Wood ash is approximately half as effective as lime in neutralizing acid. As a general rule, apply about two ounces of ash to every square yard (50-70g per square meter). Do this on a still day in winter and wear gloves to protect your hands.

Wood ash can be used around brassicas in place of lime

Using Wood Ash around Plants

Use the alkalinity of wood ash to improve soil for brassicas such as cabbage and Brussels sprouts. This is a great way to prevent club root, a common disease when soil’s too acidic. Apply it the winter before planting, or as a side dressing around actively growing plants.

Its high potassium content means wood ash is ideal to use around most fruit bushes, including currants and gooseberries, where it also helps wood to ripen, thereby improving hardiness, disease resistance and productivity. In fact, mix it into any soil used to grow fruiting vegetables, especially tomatoes.

Where Not to Use Wood Ash

Due to its alkalinity, wood ash shouldn’t be used around acid-loving plants such as blueberries and, to a lesser extent, raspberries. Don’t apply it to areas used to grow potatoes, as alkaline soil encourages potato scab. Avoid it coming into contact with seedlings too.

You’d need to add lots of wood ash to make your soil too alkaline for most crops. But for peace of mind re-test your soil’s pH every couple of years to check it doesn’t go above 7.5.

Store wood ash in a container with a close-fitting lid until you're ready to use it

How to Store Wood Ash

Finally, a word on storing wood ash. Because the nutrients it contains are soluble, you’ll need to keep it out of the rain so they don’t wash out. Containers with close-fitting lids are perfect for keeping ash dry until you’re ready to use it.

Wood ash can be a truly useful addition to the garden. If you use it too, please share your experiences in the comments section below.

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Top dressing with wood ash - which crops need it and which are contraindicated - AgroXXI

Anna Medvedeva

Summer residents usually accumulate wood ash after cutting trees or heating a stove. Do not blow ashes into the wind as they are a valuable source of nutrients for horticultural crops

Wood ash is a natural catalog of important micronutrients including phosphorus, manganese, iron, zinc and calcium. It contains a lot of potassium, which contributes to the flowering and fruiting of plants.

Interestingly, young wood obtained from pruning produces ash with a higher concentration of nutrients than old wood. Similarly, ashes from hardwoods such as oak, maple, and beech contain more nutrients than ashes from softwoods.

Avoid using ashes from chemically treated wood, which can damage your soil and plants.

Wood ash is alkaline, so using it in compost heaps helps balance the compost's tendency to oxidize, creating better conditions for worms to speed up organic decomposition.

Less acidic compost is ideal for mulching vegetables.

Add wood ash little and often, spreading thin layers on the compost heap: a few handfuls or one spade for every 15 cm of organic material.

Wood ash can play a useful role in improving overly acidic soil.

Most vegetables need a pH of 6.5 to 7.0, so if your soil is below 6.5 sprinkle wood ash. This is especially true if you are actively applying cattle manure to the beds - this type of manure is very acidic.

Wood ash is about twice as effective as lime in neutralizing acidity.

As a rule, such work is carried out by scattering approximately 50-70 g per square meter.

Use the alkalinity of wood ash to improve the soil in cabbage beds to prevent clubroot. Kila cabbage is a common disease in acidic soil.

Apply wood ash in winter before planting or as a "garnish" around actively growing plants.

In fact, mix ashes with any soil to get a rich crop of vegetables, especially potassium-deficient tomatoes.

The high potassium content means wood ash is ideal for feeding most berry bushes, including currants and gooseberries, improving plant health and disease resistance.

Where wood ash should not be used

Because of its alkalinity, wood ash should not be used around acid-loving plants such as blueberries and, to a lesser extent, raspberries.

Do not use in potato growing areas as alkaline soil encourages potato scab.

Of course, in order for the soil to become too alkaline, you will need to add a lot of wood ash. But for peace of mind, check the pH of the soil every couple of years to make sure it doesn't exceed 7.5.

Finally, a few words about the storage of wood ash. Since the nutrients it contains are soluble, protect the natural fertilizer from rain so that the nutrients are not washed out. Containers with tight-fitting lids are ideal for keeping ash dry until you are ready to use it.

(Source and photo: www.growveg.com. Author: Benedikt Vanhims).

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Wood ash

Ash from our stoves and barbecues can serve a person more than once. Imagine that you get a fertility product for your garden from time to time. And at the same time, you can significantly save on garbage disposal and the purchase of potash fertilizers! For example, wood ash contains in small quantities almost all the elements necessary for the plant, except for nitrogen. For those who do not have a stove, there is also a way out, since high-quality wood ash can be bought at almost any garden store.

Mixed with compost heap

Due to the fact that wood ash easily transfers its nutrients to water, it is not advisable to keep it outdoors - rain will easily wash away the fragile structure. It is advisable to spread the ashes in a covered compost heap or scatter over dug up beds. When adding ashes to the compost heap, it will be useful to make some layering, i.e. alternating layers of ash and plant residues. Thanks to the ash, the compost will lose a significant amount of acidity, which means it will become a real bait for colonizing beneficial microorganisms, earthworms.

Coal ash

In some countries, in addition to wood heating, there is heating with coal. The principle of its operation is the same, however, the mass obtained after burning is somewhat different from wood. The composition of coal ash contains little potassium, calcium and phosphorus, which is why it is a waste of time to use it as a fertilizer for garden plants. Experts advise considering coal ash as an option for ennobling wet clay soils. It contains approximately 40-60% of silicon oxides, due to which it noticeably loosens and drains lands previously unsuitable for growing crops.
Another interesting property of coal ash is its ability to significantly acidify soils after heavy application. Sulfur in its composition gradually forms sulfates, which can displace carbonates in saline soils and provoke the formation of soluble salts, which are quite easily washed out of the soil by moisture. Those. this ash is completely unsuitable for acidic and sandy soils, but will perfectly cope with the alkaline environment in highly saline soils.

We use coal ash

When coal ash is mixed with calcium nitrate, cattle manure, ammonium carbonate and bicarbonate, bird droppings, it can be applied to neutral and slightly acidic lands. However, with this method, the nitrogen content in it can be significantly lost. Usually they take up to 3-3.5 kg for each hundred acres of the plot, the mixture is applied in late autumn.
Garlic, onion, rutabaga, horseradish, cabbage, mustard, radish will be grateful for the use of pure ash, since these plant crops absolutely need at least a minimum sulfur content in the soil for full growth.

We use wood ash

Wood ash is often used in gardens as a fertilizer for acidic or neutral soils. Due to the absence of the element chlorine in its composition, ash can be used for plants that are extremely sensitive to chlorine, such as currants, garden strawberries, potatoes and raspberries. Wood ash has a beneficial effect on many varieties of cabbage, protecting them from the destructive black leg and keel. Patissons, zucchini, cucumbers and sweet peppers also love ash-treated soil.
Wood ash can be added to the holes when planting seedlings in a permanent place of growth (1-3 tablespoons in each hole). When planting seedlings of plums, cherries, currants, you can add 2 tbsp. spoons of ash in dry or dissolved form. For subsequent feeding of young seedlings (not more than 1 time in 3-4 years), the near-stem annular grooves are watered with a bucket of water with two glasses of ash. Mature trees fertilize 1.5-2 kg of ash.
For fertilizing tomatoes, cucumbers, cabbage and other vegetable crops, use an ash solution at the rate of 100-200 g per bucket of water. Fertilizer is poured, stirring constantly, into pre-prepared grooves, which are then sprinkled with earth. One plant usually takes 2 cups of the solution.
As regards the timing of the application of ash in the garden, for heavy, poorly fertile soils, digging in the fall is recommended, and for airy sandy loamy soils, an excellent application time is spring. It has been noticed that the ash solution not only alkalizes the soil, but also significantly increases the viability of plants, especially those that were planted from home seedlings.

Ash composition

The best and most valuable ash in terms of nutrient content is the ash obtained after burning grass, buckwheat and sunflower are especially preferred. Useful for burning and fallen leaves of trees: so in the leaves of birch, when burned, a huge amount of easily digestible potassium is preserved. The poorest content of phosphorus and potassium is peat ash, of course it can be used, but perhaps as a source of calcium for plants.
The use of ash allows plants to easily absorb phosphorus from the soil, in terms of its qualities it can outperform even superphosphate, which is so beloved by all summer residents.
For the best effect of ash fertilizer, you can use straw and wood ash mixed with humus (or peat) in a ratio of 1 to 4. Thus, it will be easier for you to distribute top dressing among the beds, and it will be easier for plant crops to absorb all the valuable nutrients from the soil.

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