iGrow Gardening: What to do about voles?

David Graper
SDSU Extension Horticulture Specialist

Q I have a friend who has voles in her yard, and it sounds like a lot of the yards in St. Onge. What can they do about them? I think it is funny, but the voles are active this winter, under the snow.

A Winter is the time of year when they normally do the most damage. These active little critters might take a winter nap from time to time, but they usually are fairly active all winter long. Just as snow offers protection and insulation to our garden plants, it provides a nice place for the voles to feed and survive during the winter months. Often, they feed on the turfgrass beneath the snow so that in the spring one will find all of these paths that have been “mown” off during the winter. The turf will generally fill back in again once it starts growing in the spring. You can over-seed it with more grass seed if you wish to speed the process up. Rake out the loose grass before doing so though. The most serious damage they cause is when they decide to chew on the bark of woody plants. This can kill some plants if damage is severe.

It is pretty hard to do much about them now with the snow cover. Prior to snow in the fall, you can actually put down packets of mouse or rat poison, but you have to be careful to keep them covered up, so pets do not get into it. You can try putting the bait under boards or other barriers to keep the pets away but leave room for the voles to get at it. Also, if pets or other animals eat the poisoned voles, that can be dangerous for the pets too. You can also use the box type mouse traps that have a small door where the voles can go in but then they cannot get out again. These are much safer than the poison, but you need to check them periodically. During the summer, you can also work to decrease their habitat. They like taller grass and other cover, so cleaning up areas around your yard can be helpful. A good cat or three can help a lot too, but unfortunately cats are sometimes hard on song birds.

Can I plant old seeds?

Q Before I go and order new seeds, I always check and see what I have left over from last year. All seed companies expect that you will plant all the seeds in the package that year. I for one, couldn’t handle all the produce that would come if I planted all 25 seeds in a tomato package. I cannot throw out seeds that are leftover, so I inevitably have opened seed packets from years ago. The question become how old is too old and will the seeds grow?

A There are three factors that play into whether your seeds are still viable. The first one is age. How old the seed is will give you an idea whether your seeds will germinate. All seeds are tested and expected to grow the first year. Most seeds will grow the second year too. Every year after that, percent seed germination will drop.

The second factor is what type of seed you are wondering about. For example, pepper and corn seeds will have a harder time growing if the seed is over 2 years old. On the other hand, cucumber and lettuce seeds can last up to 6 years.

Lastly, how you store your seeds will contribute to the length of time that the seeds will be viable. The best way to store seeds which you bought or saved is to place them in a cool, dark place. The appropriate way to overwinter seed is to place the seeds in a sealed jar. The sealed jar should have a desiccant, like powdered milk or rice, to absorb any moisture that may develop in the container. Then, place the seeds in a location that is 50°F and 50% humidity. Your refrigerator produce draw has these conditions. Seeds may also be stored in a freezer for even longer-term storage. Unfortunately, left-over seed is often just be stashed in your garage or basement somewhere. This may expose the seed to fluctuating temperatures and moisture conditions, that will shorten viability. Rodents may also you’re your seed and eat it before you have a chance to replant it the following year. When seeds are not stored in ideal conditions, they will decline. You may notice if you plant them that they may take longer to come up, the seedlings may be deformed, or the seed may fail to germinate at all.

Before you spend time on planting those old seeds and get nothing in return, try doing a home germination test. This test is an easy way to determine the viability of your seeds. The test will require you to sacrifice a few of your seeds. Remember that our growing season is not that long. So if you take a chance and plant non-viable seed, then wait a week or two for it to come up, waiting and then replanting will shorten the time you have to grow a successful crop.

Home germination test

  • You will need two paper towels. Using a pencil or water-resistant marker write the name of the seeds and the day you are starting the test on the paper towel.
  • Moisten the towel with tap water. Too much water will promote bacterial or fungal growth. So, if you press the paper towel and water swells up, start over because that is too much water. It may be easier to use a spray bottle with water in it to moisten the towel.
  • Count out your test seeds. Major companies use close to 200 seeds to get an accurate germination count. You can use 5, 10 or 20 seeds. The more seeds you use the more accurate the test will be. Leave an inch border around the towel. Begin by placing the seeds 1 inch from the top of the wet paper towel. Smaller seeds should be place ½ inch apart and the larger ones 1-1 ½ inches apart. You may have one or two rows depending upon the number of seed you started with, or start another moist towel.
  • Next, fold the paper towel in half from the bottom up covering the seeds.
  • Place the moist towel, flat in a clear Ziploc bag, plastic bag or plastic wrap. Seal the bag. This serves as a homemade germination chamber.
  • Find a location that mimics the seeds germination requirements. For warm season crops, the top of refrigerator or computer tower works nicely. For those cool season crops, a basement or north facing window sill is ideal. Most seeds will want indirect light, but never place them in a location that gets direct sunlight.
  • Check the towel’s moisture every day. If it has dried out, add water from the spray bottle.
  • Check the seeds every day for up to two weeks. Some seeds will begin to sprout as in as early as three days into the test. Keep track of how long it takes the seeds to begin growing. This will give you a good idea of how long it will take them to germinate when you decide to plant them in soil. Note how many of the seeds sprout. Remove any seeds that have begun to mold. Count them as dead.
  • To calculate the germination percentage, divide the number of healthy seedlings by the total number of seeds in the test and multiply by 100, ([Healthy seedlings/Total seeds] x100 = Germination %). Example: You start with 25 seeds. 20 of those sprouted. The germination rate is 80%. The lower the germination rate, the lower the amount of seeds will grow once you plant them.

When you have seeds that have been around for a while you can still use them. Some things to remember is that seed packets are stamped with the year they are packaged. Check the above chart to see if it falls within the average limits. Store your unused seeds in an appropriate way. Doing a home germination test is easy, fun and will save you time. This could also be a fun and educational activity to do with your kids and help them to get interested in gardening. If you take these steps, you will have a greater chance of knowing which of your seeds will grow, once you get ready to start your garden.

In the seed storage cooler at national Crop Seed Repository.
Storage in air-tight containers in a freezer also works well.
Typical seed longevity in storage.
Vole damage in a lawn.
Vole damage like this will likely kill the shrub.
Vole damage.