Wood ash is a by-product of the burning process in fireplaces and wood stoves, and it can be applied as a fertilizer to your plants. Whether or not this substance is good for roses is debatable, as there are many different opinions on this topic.
It does appear that wood ash could have been helpful in previous years when chemical fertilizers were not widely used, but today its usefulness may be limited due to the presence of trace amounts of heavy metals found in ashes that may harm plants.
Do Roses like Wood Ash?
Whether or not wood ash is good for roses may depend on your definition of “good”. Many people believe that the increased nutrient content in wood ash can be helpful to roses provided it is applied sparingly and not in amounts that would exceed the plant’s tolerance for a particular nutrient.
Old-timers will tell you that wood ash was used as a source of potassium by farmers who did not have access to chemical fertilizers back in the days before modern agriculture existed, and they will also tell you that rosebushes prefer potassium over phosphorus. Potassium helps support strong cell walls and increased photosynthesis, while phosphorus supports new growth development.
How to Apply Wood Ash to Your Rose?
It is best to mix wood ash with water and let it stand for a day or two before applying it to your plants. This causes the pH level of wood ash to drop from around 9 (highly alkaline) down into the 5-6 range (neutral).
Mixing high-pH substances like wood ashes with soil or potting mixtures that already have a low pH can cause problems in some plants due to chemical reactions that occur between the two substances.
When you are ready to apply the wood ash to your rose bushes, you can mix it with compost and balanced fertilizer, or you can use it alone. Roses tend to prefer a high-nitrogen fertilizer to wood ash, so combining them may provide the best results.
When to Apply Wood Ash to Your Rose?
Wood ash can be applied to rose bushes at any time of the year, but it is best to apply it when the roses are dormant, which usually occurs during winter or early spring.
How Much Wood Ash is Safe for My Roses?
Various experts have different views on this topic, but most agree that the safest course of action would be to limit wood ash application to 1/4 cup per plant, which is not enough to harm most plants that are used as groundcovers or hedges. Applying more than 1/4 cup of wood ash per plant could exceed your rose bush’s tolerance level for one or more nutrients.
Some experts recommend limiting wood ash application to once per year, while others say it can be applied more than once if a plant needs additional nutrients. It should also be noted that until chemical fertilizers became widely used, many rose bushes were grown very successfully without the use of any supplemental fertilizers.
Is it safe to use Wood Ash on Potted Roses?
It is generally considered safe to apply wood ash to potted roses as long as it is mixed with potting soil and compost materials in order to prevent nutrient imbalances. However, it would still be best to limit wood ash application to no more than 1/4 cup for each plant, which is a small amount compared with the size of most potted plants.
Are there any Positive or Negative Side Effects?
Wood ash is alkaline and it can contribute to the buildup of salts in the soil if it is not applied sparingly. This buildup may cause some problems in certain plants that are sensitive to salt buildup.
Excessive wood ash application could also lead to excessive leaf chlorosis when it is applied at the wrong time, such as when roses are already receiving too much nitrogen, which would make them appear yellow. It is important to note that wood ashes contain many trace minerals, so you should not expect solutions from wood ash alone if your plants have nutrient deficiencies.
Which plants like wood ashes?
Wood ashes are most commonly used on roses, but other plants may also benefit from their use. Some gardeners like to add wood ashes to their compost piles.
Some recommend that you use them sparingly in vegetable gardens, but others advise against it. It would be best to check with your local Cooperative Extension Service or master gardener before using wood ashes in your vegetable garden because some trace minerals in them could have an adverse effect on sensitive vegetables.
