Organic Gardening in Central Oregon

Chapter Eight - Maintaining the Garden

Mulching

A mulch is a layer of material placed on the soil around the plants. This is a basic practice in organic gardening and in nature. Mulch will protect the soil from extremes in temperature, which are hard on plants. In the hot summer you can go out in the garden, lift the mulch and find worms working close to the surface, whereas in unprotected soil they go down deep when the weather is very hot or cold. As mulch breaks down it enriches the soil by adding organic matter.

A good mulch reduces weeding, if piled deeply enough so the weeds can't grow through. Those weeds that do manage to grow are easy to pull, because their roots are shallow underneath the mulch. It will also help to maintain soil moisture, both retarding evaporation and by catching and holding the available moisture. A mulch will help to keep your fruits, vegetables and herbs clean by covering the soil which prevents mud from splashing up.

Straw and hay are the best to use if you can get them. Often farmers have moldy or rain damaged bales that they will sell cheap or better yet, give away. Straw has the advantage of being weed free, while hay often has weed seeds which can grow. If this happens, turn the mulch over, this will usually smother the weeds. Hay or straw in bails will peel off in flakes of compacted material, just spread these flakes close together without pulling apart. The thick, compacted material will be more difficult for weeds to grow through.

Grass clipping can be used if they have not been sprayed with any weed and feed type product. They do get slimy however, and it helps to mix the clippings with coarser materials. Weeds are also be used as mulch, unless they have already formed seeds or are of the type that will regrow from the plant or leaf such as purslane. Leaves are a good mulch as they break down slowly. If you have problems with them compacting, try shredding them or mixing them with hay.

Sawdust, wood shavings or bark dust are other mulch materials often available in Central Oregon. They are great for pathways, a six inch layer will smother weeds effectively. Use caution with wood products directly around your plants, however. Wood products are very low in nitrogen, and since it takes nitrogen for them to break down, they can steal it from the soil and deprive your plants. You may want to spread cottonseed, bloodmeal or compost under the shavings. Watch your plants closely, if they show signs of nitrogen deficiency (yellowing of leaves), feed them extra.

Pine needles are frequently available and can be used also for mulching. They break down slowly and get a little slippery, but are good for paths particularly. They are also good for ground that you want to acidify, this often being the case with alkaline soils. Studies indicate that they do not leach harmful substances in damaging quantities.

Newspapers can be spread out and weighted for use as mulch also, but do not use colored inks or slick paper, just regular newsprint. I have even seen old carpeting and tar paper used in the garden to good effect. Sheet plastic creates a real barrier to weeds when placed under mulches like bark dust. When spread over weedy areas, the weeds die under the plastic, clearing areas for cultivations with a minimum of effort. Black plastic is particularly effective for this as the heat builds up under the black color and will with luck destroy weed seeds also.

Stones and gravel are another type of mulch. Large stones give thermal mass and hold heat during the night. Gravel has the obvious limitation of not breaking down, so it is not appropriate to use where you want to dig the soil under again.

Some people garden under a heavy, year around mulch. Pushing it aside only when they want to plant. Ruth Stout is a fascinating gardener that has written several books about using the year around mulch system. The year around mulch method may not be as successful on low lying damp soils, as it can encourage damp off and crown rot of perennials. In a sandy soil, and with rich soil to begin with, this system may be worth exploring.

Seasonal mulch can be put down immediately upon seeding if the ground is already warm. In early spring, you may need to wait until the soil warms up before spreading mulch. When transplanting seedlings, I like to lay the mulch around them immediately. Then if frost threatens, the mulch can be pulled up close for protection.

Tips for judging a good mulch:

1. The mulch should have enough weigh so that it will not blow away.
2. The mulch should remain loose enough to allow air circulation down to the soil surface.
3. The mulch should be free of toxic chemicals.
4. The mulch should be fairly easy to obtain and apply.

Water

Building your soil with organic matter is an extremely important step in the process of keeping your plants watered. A soil rich in organic matter will act as a sponge, absorbing the water that does fall on it. The mulch also has an important water conservation function.

Keep in mind that too much water can be as detrimental as too little. Plants and soil organisms need oxygen for their survival; a soil constantly saturated with water has no oxygen holding capacity. Too much water will leach the nutrients out of the soil and drain them away with the water.

The general rule is to water deep and less frequently. This forces the roots to grow down deep and helps protect against drought. A lawn or garden with a deep root system will survive longer in drought conditions than plants with shallow roots encouraged by frequent, shallow watering.

A mistake made frequently in Central Oregon is to start watering too late in the spring and to stop too early in the fall. If you are regulated by an irrigation ditch, you may have no choice; but if it is your option, water throughout the time the ground is not frozen. Sandy soil dries out even in winter and can leave trees and perennials in seriously dry condition.

Generalizations about about how many inches of water a week your garden needs is difficult as it varies with the soil and other conditions. Dig down to see how deep soil moisture is after watering. It is often surprising when you think you have watered well, but after digging down you may find the water is not deep at all. Fruiting and blooming plants require more water than usual.

Wilting in the heat of the day does not necessarily mean that the plants need water. Some plants wilt from the heat. Dig down to see if the soil is really dry.

Experts do not agree as to when the best time to water is; some say in A.M., others say P.M. The morning hours give time for the foliage to dry before dark, which can be important if you are having problems with mildew. P.M. usually has less water evaporation loss. If you live in town, you will have to water by the regulated hours.

As water becomes increasingly scarce, the equipment you use to water with becomes more important. Overhead irrigation can loose as much as 30% of the water due to the wind and evaporation. Drip irrigation systems or soaker hoses aid in water conservation. Also helpful is a timer on your hoses.

Mid-Season Fertilizing

Organically built up soils will feed the plants, but during peak growing times you may want to provide an extra boost. You can side dress two or three times a season with dry fertilizers such as cottonseed, bone or blood meal. Dig a furrow about three inches deep as close to the plants as possible. Put the fertilizer in and cover with soil, water well.

Liquid solutions such as manure and compost tea or fish fertilizers, are an easy and effective way to feed plants. To make tea, fill a bucket about half full of compost or manure and cover with water. Let this set for about a week. Strain the water off and mix with water until it is about the color of tea. Water your plants with this about every three weeks.

Foliar feeding can provide a quick fix by helping to correct minor mineral deficiencies and bolster plants in times of stress. This is done by spraying a solution of plant food onto the leaves of the plant. Commercial preparations of concentrated liquid kelp and seaweeds are excellent for this purpose. Not only will it give your plants a little snack, but seaweed solutions will improve seed germination, decrease transplant shock, increase fruit set, and best of all increase frost resistance. Foliar feeding is most beneficial in midsummer, as this is the highest stress time for most plants.

Frost Protection

The trickiest part of frost protection is figuring out when it is going to frost. I have gone to bed when it was 55 degrees, and woke up to frost. This is a very discouraging affair to belatedly realize that frost has struck and find your beautiful garden frozen solid.

Listening to local weather reports does help sometimes, but not always. You will need to become your own weather expert. You may be able to find a neighbor or friend, especially one who has lived here a while, to help you figure out the climate peculiarities.

There are some special things to watch for. If the time is near the full moon, prepare for frost watch as the likelihood of frost is higher at this time. If you have an evening with calm air, no breeze, a clear sky and an early evening drop in temperature, watch out. Many a night I have set my alarm for three in the morning to run out to check the temperature and saved my garden as a result.

Water is one way to protect you garden. If you have the watering option, you can let an overhead sprinkler run overnight, this can result in overwatering however. I find it best to turn it on in the middle of the night, before it has gotten too cold to freeze the sprinkler. This may result in ice around your plants, but the process of freezing creates heat and will protect the plants to about 27 degrees.

Some people have fair luck with watering well the night before, and the water on the leaves is enough protection. If the worst happens and you get up to frost, sometimes it helps to sprinkling frozen plants with water before the sun hits them. Once the sun hits frozen plants that are tender, the cells burst and it is too late.

Another solution, if you do not have too many tender plants, is to cover them. I have a large collection of old sheets and clothes that I save just to cover plants. Old blankets, newspapers if weighted down, hot caps and milk jugs with the bottom cut out, are just a few of the many creative choices of materials to choose from.

Rainfall Averages

Fall and Winter Care

One of the things I like most about gardening in Central Oregon is the definite winter period. There are about three to five months out of the year you don't have to do too much. Now you can, of course, putter at some garden related tasks much of the year, but you can also just move on to other interests in the winter months.

There are a few late summer and fall chores that can be done. Such as sowing an overwintering cover crop, like winter rye. I have gotten rye to germinate even as late as October, when the weather cooperates.

Winter mulch is applied after the ground freezes. Just mulch over the top of the plants with hay, evergreen boughs or something that will not mat down. This helps the ground to stay frozen and protects perennials from heaving. Heaving is when plants actually come up out of the ground from the action of thawing and freezing, which exposes the roots to drying out and can be quite harmful.

Leaves can be used as a blanket to cover the garden for winter. Spread them over the whole garden and by spring they will have almost disappeared into the soil. Sandy soil can consume vast amounts of organic matter to good benefit.

Give mulch protection to the perennial vegetables you want to overwinter such as asparagus, kale, spinach, parsley, onions, garlic and jerusalem artichokes.