Is Wood Ash Good for Tomatoes?

I’d love to warm myself in front of the fireplace or wood burner. Who don’t? But, the bonfire leaves lots of ash that can be a bit of nuisance to get rid of them.

As a gardener, you don’t have to worry about it. Instead, you can use wood ash to fertilize your tomato garden.

Is wood ash good for tomatoes?

Yes, wood ash is packed with potassium (potash), magnesium and calcium that can help your tomato or any vegetable garden to produce quality yield. These elements provide essential nutrients to your tomato plant that leaves good impact on its foliage, fruit color and yield.

What Nutrients Does Wood Ash Contain?

Every year tons of wood ash waste is left, which is applied to land in US. Land application is the best way use wood ash, because we can recycle the nutrients taken during harvest back to the land.

According to this study, wood ash is similar to lime application. However, wood ash has more nutrients than limestone. It is also water soluble and helps to increase pH of your garden soil.

Packed with significant amount of potassium and calcium; wood ash can be used as soil amendment. It also contains magnesium, phosphorus, zinc and copper in small amounts.

If your garden soil is low in nutrients that you can use wood ash to increase its fertility.

Many gardeners regard wood ash as primary substitute for lime stone. Compared to limestone, wood ash can quickly reduce the acidic nature of your soil and increase soil pH.

Also Read: Are Banana Peels Good For Tomato Plants?

Potassium Role in Tomato Production

  • A report states that high amount of potassium will help to increase yield and plays important role in ensuring top quality ripped tomatoes.
  • Low levels of K can results in white or yellow tomatoes.
  • When you provide good amount of potassium to your tomato garden, you’ll be gifted with juicy tomato fruits.
  • Tomato plant diseases that are alleviated due to higher dose of nitrogen can be lowered by applying potassium rich fertilizers like wood ash.

Calcium Role in Tomato Production

  • Calcium has important role in growing and yield of tomatoes. It is very essential to improve early fruit development in tomato plants.
  • Calcium application positively impacts fruit quality and firmness of tomato plant.
  • This nutritional element helps to reduce the risk of tomato disorders and aid in healthy tomato plants.

Magnesium Role in Tomato Production

Magnesium is essential in protein synthesis and chlorophyll production. Its use ensures even ripped tomato fruits.

While phosphorus helps to ripe tomatoes, zinc application will aid growth of plant and development of chloroplast.

Read more about nutrients in wood ash here.

Also Read: Is Epsom Salt Good for Cucumbers?

How to Use Wood Ash for Tomato Plants?

wood ash for tomato plants

You must be careful while using wood ash for any vegetable garden. Obviously, you shouldn’t use hot or warm wood ash on plants.

Few gardeners state that wood ash from hardwood has more nutrients when compared to ash from softwood.

#1 Wood Ash in Compost

Your compost heap should be a catalog of nutrients that can benefit any plant in your vegetable garden. Balanced nutrient rich compost isn’t possible without including alkaline elements.

Wood ash inclusion to compost will help to reduce the acidic tendency of your compost. Apart from this wood ash provide perfect growing conditions for composting worms, which help to speedup decomposition.

How to Use: Add one shovelful of wood ash for every 6 inches of compost.

#2 Wood Ash to Increase Soil pH

Most vegetable gardens prefer soil pH of 6.5 to 7.0. Balanced pH of soil helps to effectively absorb the nutrients applied.

Tomato plant does well in soil pH ranging from 5.5 to 7.5. Adding wood ash to your garden soil will help to increase this value quickly when compared to limestone.

How to Use: Test your soil pH, if it’s lower than 6.5, then sprinkle wood ash on surface of the soil and then rake it in. Wear gloves to protect your hands from wood ash.

#3 Wood Ash to Fertilize Tomato Garden

As mentioned above, nutrients in wood ash contribute in growing, flowering, yielding and ripening of tomatoes.

There are several reports that back the claim that wood ash application to your tomato garden will benefit in producing hearty tomatoes.

How to Use: Side-dressing wood ash around actively growing tomato plants. Spread think of garden soil over the applied wood ash. You can add 50 grams of wood ash per one square meter.

Note: Test soil pH before applying wood ash to your tomato plants.

#4 Wood Ash as Pest Repellent

Several agricultural experts recommend using wood ash to control common pests like aphids and slugs. Salt content in ash successfully helps to avoid insects and pests.

Though not effective, wood ash application along with neem ash is a good natural pesticide with zero side-effects.

How to Use: Sprinkle wood ash at the base of the tomato plant. Look tomato leaves for slugs or insects. If needed garlic water or other natural pesticides on leaves to gets of them.

Also Read: How Many Tomato Seeds per Hole?

Nutrients Needed for Growing Tomato Plants

Now, that you’ve grown through nutrients in wood ash and how they help your tomato plants.

I think it’s fair to know essential nutrients that your tomato plant needs. Without knowing the required nutrients, you may end applying unbalanced fertilizer to your plant.

You must know this; best fertilizer for tomato plant must include macronutrients like nitrogen, phosphorus and potassium. Other micronutrients like zinc, magnesium, calcium and boron are also needed.

  • Tomato plant needs nitrogen for continuous growth of its foliage.
  • Potassium aids in photosynthesis and make the plant disease resistant.
  • Root and fruit development is done by balanced amount of phosphorus in the fertilizer.
  • Calcium plays vital role in growth of leaf and roots. It also helps in production of firm tomatoes.
  • Magnesium, essential to improve flowering and tomato fruit quality.
  • Zinc and boron helps in ripening of the fruit. (Source)

After going through these essential nutrients, you’ll know that wood ash all necessary nutrients except nitrogen. If you notice that your tomato leaves aren’t growing, application of nitrogen rich fertilizers.

How to Store Wood Ash to Fertilize Tomato Plants?

First thing, it might be difficult for you to obtain wood ash in urban areas. Take help of your neighbor or gardening friend to get wood ash from bonfire.

Packed with a catalogue of nutrients, wood ash helps your vegetable garden in many ways as already mentioned above. But, after your first application of wood ash, how to store them?

  • Wood ash is water soluble, so keep it out of rain so that they don’t wash out.
  • Containers with tight closing lids are perfect for keeping wood ash dry until next use.
  • You can also use metal containers to store wood ash.

Higher Dose of Wood Ash for Plants

It’s a long term fertilizer that consists of potassium and phosphorus. However, high dose of wood ash will result in decline of biomass. So, it’s recommend using medium dose of wood ash along with nitrogen fertilizer. (Source)


To keep it short.

Wood ash is an excellent source of nutrients for growing tomato plants.

WA is packed with potassium, phosphorus, calcium, zinc and magnesium. These elements used to grow foliage, ripe tomatoes and increase quality of fruits.

Along with wood ash, you must use nitrogen rich fertilizer. If you’re using WA to reduce acidic nature of the soil, then conduct soil pH test. Unlike limestone, wood ash application will increase soil pH quickly. WA is best alternative to limestone.

Leave a Comment