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Are wood ashes good for compost


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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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.

Use of ash as a fertilizer: instructions with proportions

Gardeners and gardeners are well aware that ash is an excellent fertilizer, cheap and accessible to everyone. In addition, ash also neutralizes the soil, that is, it is useful to apply it on slightly acidic soils (other deoxidizers must be used on strongly acidic soils).

Generally speaking, after burning, there remains a mineral fertilizer, which usually contains up to 30 nutrients needed by the plant. Among them are potassium, calcium, phosphorus, magnesium, iron, silicon, sulfur, and various trace elements. There is practically no nitrogen in the ash, its compounds volatilize with smoke.

However, ash is different and its value depends on what exactly was burned.

Content

Plant residue ash

For example, ashes obtained by burning grass, straw, leaves contain a lot of potassium. By the way, excellent ash is obtained from potato tops: it contains about 30% potassium, 15% calcium, 8% phosphorus, and a large number of trace elements needed by plants.

The ash obtained by burning buckwheat straw and sunflower stalks is very rich in potassium, although it contains slightly less potassium than wood ash. Rye and wheat straw contain a maximum of phosphorus - up to 6%.

Woody

Hardwood ash (elm, oak, ash, beech, maple, poplar, larch) contains a lot of potassium (most of it is in elm ash).

In the ashes of softwood (linden, spruce, pine, alder, aspen) potassium is also present, but in a smaller amount. However, it is worth mentioning separately about birch: although it belongs to soft rocks, the ash from it turns out to be excellent - it contains a lot of potassium, phosphorus and calcium.

The ash obtained from the burning of young trees contains more potassium than the ash of mature trees.

Application

The effectiveness of ash is increased when used together with manure, peat, compost and humus.

Further, the ashes are used as top dressing: during the first hilling of potato plants, 1-2 tbsp. l. ash, and during the second hilling (at the beginning of budding), the dose is increased to 0.5 cups under the bush.

Ash content 1 tbsp. l. - 6 g matchbox - 10 g faceted glass - 100 g half-litre jar - 250 g

Composting

The elements contained in wood ash are soluble in water, so the ash should not be stored outdoors. It is better to immediately lay it in a compost heap or bring it to the ridges.

Wood ash is useful to spread into the compost heap, covering every layer of food waste and lawn clippings or weeds. Ash slightly reduces the acidity of the compost, creates favorable conditions for the development of microorganisms, the work of earthworms.

Coal

Ash obtained by burning coal requires special discussion. It is low in potassium, phosphorus and calcium, that is, it should not be used as a fertilizer. However, coal ash contains up to 60% silicon oxides, so it can be used instead of sand to drain and loosen wet clay soils to improve their structure.

One more feature of this ash should be mentioned: there is a lot of sulfur in coal, so sulfates appear in the ash, as a result, coal ash does not neutralize (unlike wood ash), but acidifies the soil. Thus, coal ash should not be applied on acidic and sandy soils, but it is suitable for saline soils (ash sulfates displace carbonates, soluble salts are formed that are washed out of the soil with rains, and salinity decreases). Salt soils most often have an alkaline reaction, so coal ash is useful from this point of view too - it acidifies the soil.

Application

On slightly acidic and neutral soils, the use of coal ash is permissible if calcium nitrate, ammonium carbonate and bicarbonate, manure and bird droppings are simultaneously applied. This can be done in small quantities - up to 3 kg per hundred square meters, before winter.

Coal ash is also used as a high sulfur fertilizer for onions, garlic, cabbage, radish, swede, mustard, horseradish, which require this element.

Source: Gardener's assistant No. 23(2012), Lyudmila Kalugina, agronomist, Moscow

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Ash improves soil structure, creates favorable conditions for the development of microflora, especially nitrogen-fixing bacteria that improve nitrogen nutrition of plants.

The effect of this fertilizer is felt within four years after its introduction into the soil.

Ash

No nitrogen, but up to thirty other different elements. These are elements such as: potassium, calcium, magnesium, iron, silicon, phosphorus, sulfur, boron, manganese and so on. Phosphorus from ash is absorbed by plants better than that contained in superphosphate. It does not contain chlorine, to which raspberries, currants, strawberries, and potatoes react poorly. It is known that 70 grams of ash applied per square meter of sandy, sandy and podzolic soils fully satisfy the needs of most plants in boron, which means that it is very useful for cabbage and tomatoes.

Heavy and podzolic soils respond best to ash: as a lime fertilizer, it reduces acidity - in the ashes of firewood, lime can be up to 40%.

Burnt potato tops contain more than 20% potassium, 8% phosphorus and 32% lime. Therefore, after harvesting, you need to rake the tops and burn it right there on the site. This ash is good not only for potatoes, but also for carrots and beets: in autumn or spring, up to 700 grams of ash is plowed per square meter of poor soil. For peas, you need 150-200 grams, and for fruit trees - 100-150 g per 1 sq. meter.

The complex of macro- and microelements of ash has a good effect on strawberries after trimming the whiskers, on potatoes - when loosening row spacings. To do this, use both dry ash and an aqueous solution, which is prepared immediately before use (50-150 g per bucket of water). When top dressing, the liquid is constantly stirred in order to evenly distribute the solid residue containing phosphorus between the plants. Cabbage, cucumbers, tomatoes are treated with this solution at the rate of 0.5 liters per plant.

It is not recommended to add ash to liquid organic nitrogen-containing top dressings (slurry, liquid composts), because nitrogen is lost because of this. It is not necessary to mix it with phosphorus preparations (superphosphate, etc.) - plants absorb it worse. Ash can be mixed with other mineral fertilizers, but only before being applied to the soil. It is impossible to make ash together with lime, as well as in soils that have recently been limed, so as not to increase their alkaline reaction.

Ash mixed with compost soil is good: it accelerates the decomposition of organic matter and enriches the compost with microelements.

If you apply ash to the soil, try to cover it to a depth of 8-10 centimeters. On the surface, it forms a crust that prevents the soil from breathing.

Loamy and clayey soils can be treated with ash in spring and autumn, mixing it with sand, sandy soil - in spring, 100-200 g per square meter.

If one part of ash is mixed with two parts of well-rotted wet peat or humus, the fertilizer will not burn plant roots or tubers.

Usually a lot of ash accumulates in the household, and you need to make sure that it does not get wet - otherwise potassium, one of its most important components, is lost.

Ash is often used as a plant protection agent, for example, strawberries are pollinated against gray rot, viburnum and other shrubs, especially those suffering from harmful insects. When plants are affected by powdery mildew, they are sprayed with ash liquor. It is prepared like this: 300 g of sifted ash is boiled for half an hour, insisted for about an hour, filtered and topped up with water up to 10 liters. To make the lye stick better, 40 g of planed soap is added to it. Sprayed in calm, clear weather, when rain is not expected. This treatment can be done twice a month. Lye, by the way, repels insects from the seedlings of vegetable crops.

If birch wood ash is added under potatoes, tubers grow better, they contain more starch, plants suffer less from late blight. Cabbage fertilized with ash is less likely to get keel, and beets - heart rot and tail rot.

Potato plants pollinated with ash are believed to kill Colorado potato beetle larvae and even some adult insects.

Ash is also used as an antiseptic: it is powdered on sections of flower bulbs, peony tubers, dahlias, irises and potatoes, when they are planted in parts of the tubers.

If a pumpkin has a bed sore, the affected area is cut out and sprinkled with ashes.

Compost

In a small household plot, soils are quickly depleted. Some agronomists believe that compost is only slightly inferior in value to manure. If desired, compost can provide the needs of the garden in organic matter for the entire season. We just need to remember a few important things.

Layers of waste in the compost heap should alternate with earth, sawdust or peat. They can be sprinkled with ash, superphosphate (trying not to mix the last two substances in one layer), wetted with slurry. The compost heap must be closed from the sides and be above the ground with the turf removed, otherwise earthworms and various microflora from the earth will not be able to penetrate into it, which improves the aeration of the compost. Make the top of the pile in the form of a trough so that the water does not drain, but evenly wets it. A plot of land with a compost heap, necessarily warm and semi-shaded, can be planted with beautifully flowering annuals, such as sunflowers or Jerusalem artichoke.

Don't be upset if the heap is not fully rotted: fresh compost that has been stored for 6-9 months has more microorganisms than compost that has been stored for over a year. Such compost will be absorbed quickly, especially if you dig up a pile twice a season.

Recently, gardeners and gardeners often use the so-called wet composts. They are prepared in large barrels. Weeds pulled out during weeding (before flowering!), cut tops, leaves and other non-lignified waste should be put in a barrel (about a third of its volume), poured with water, covered with foil and placed in an open, well-heated place by the sun. After about two weeks, when the contents ferment and a specific smell resembling manure appears, the garden and garden trees are watered with liquid. Many gardeners dilute such a concentrated infusion with four to five volumes of water. After the next weeding of the beds, the newly collected weeds are placed in a barrel, filled with water, and the fermentation process is resumed.

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