Ask the gardening expert



I have backyard gardens — some raised, others on grade — in the city, where I grow all kinds of vegetables.

I would like your recommendation on the use of untreated chicken manure that I buy from a farmer in the county.

Is this a recommended fertilizer? Do I need be concerned about latent chemicals the farmer may use to raise the chickens?

What is the best time of year to fertilize for next year’s crops? It is a pretty potent fertilizer? Should it be used every year?

Do you have an alternative fertilizers that you would recommend ?

I always use some Osmocote when planting my crops.

Fresh chicken manure is pretty potent stuff, There are also so many pathogen possibilities in using the fresh stuff. It’s usually recommended that you stockpile it for a year or two. Even then, I guess I would hate you see you growing veggies below the soil, such as potatoes, beets, onions etc. Vegetables that are grown above the soil are considered somewhat safer, such as string beans, corn, tomatoes, squash. These are safer because they are developed above the soil line and not in the soil. It is not the chemicals the farmer may use so much as it is the disease potential in the manure itself.

However, remember the above recommendations are all with the aged manure only. The fresh stuff is not safe to use in growing food for the table. I’d feel better if you would take precautions and not allow children or pregnant women to eat garden products produced using chicken fertilizer in any stage if it’s not properly aged and made into compost.

I cannot see a reason to use pellet fertilizer, such as Osmocote, once you get your chicken manure properly aged and safe for use. I’d recommend you buy bagged products — beef, horse, or chicken — until your product is ready.

Master Gardener Program coordinator Erika Johnson has given me permission to use a question she placed in the MG newsletter. Erika says:

We have enjoyed a beautiful and colorful fall here in Southwest Washington, and now it is time to enjoy the autumn leaves in another way. A recent visitor to the answer clinic brought in some large maple leaves to ask if they are good for composting or mulching. How would you have answered this question?

Composting leaves is an excellent way to recycle your garden waste into an organic soil amendment and conditioner. Leaves will decompose slowly, but decomposition time can be greatly reduced by shredding. Rake dry leaves into low piles and mow over them. Shredded leaves can be spread on your lawn, used as mulch or added to the compost pile.

I can nearly count on being asked similar questions at certain times each year. The leaf question; also the spider question as fall approaches, and this one:

Now that we are using our wood-burning stoves again this fall, I’m wondering about using the wood ashes in the garden plot now that all the vegetables are cleared out of the way. I know I’ve heard the answer before, but don’t recall what you said. Could you run that answer again to remind me?

I cannot spot that answer in my archived work either, but will run what Garden Gate Magazine said in their October 2009 edition.

The question is, “Can I use the ashes in my garden?” The answer is yes, in limited amounts. Wood ashes have elements that plants need, including calcium and potassium. But they are also concentrated and can easily become too much of a good thing. Shrubs and roses need only one cup a year for each plant, worked lightly into the soil in fall and thoroughly watered in.

Ashes are also very alkaline; this could help out very acid soil, but don’t use them around acid-loving plants such as blueberries, azaleas, camellias, rhododendron and hydrangeas to name a few. The ashes make the pH of the soil too alkaline for those type of plants. Set aside a separate spot for dumping ashes, away from plants. Never store them in a flammable container such as a cardboard box, anything plastic or a wood box. Also, never leave the contained ashes on a wooden porch, deck or in a garage. They can come to life and begin a fire long after you think they have gone out.

Celeste Lindsay is a WSU-certified master gardener. Send questions to