Good horticultural practices for rose growing, as well as other plants and vegetables, nearly always stress the importance of adding organics. For instance, the application of an organic mulch is recommended as a top dressing to improve both water conservation in the hot summer months but also to provide the soil with an ample supply of decaying compost. As decomposition of theses organics take place, the production of humic acids is the end product. It is often referred to as “Humus”. As leaf litter (including deliberate beneficial applications of cotton seed meal and alfalfa) and other vegetable crops decay, the process first produces Duff (a partially decomposed mixture) followed by Leaf Mold (a mixture of Duff with beneficial fungal properties) and then finally Humic Acids. But Humic Acids are not that simple to define being a mixture of complex macromolecules. While Humus Acids are the end products of decomposition of soil organic matter derived either in a composting environment or occurring naturally within the soil, they represent a mixture of four main distinct components.

• Humic Acid not soluble in water under very acidic conditions (pH<2) but soluble at higher pH levels. This portion of humus is the major extract used in horticulture. The color is dark brown to black.

• Fulvic Acid is the portion that is soluble in water under all pH levels. The color is light yellow to yellowish-brown.

• Ulmic Acid – also known as Hymatomelanic acid, a minor fraction that is soluble in alkaline.

• Humin is the remaining fraction that is not soluble in water at any pH.

Humic Acids Enhances Fertilization

To rose growers the major benefits of adding Humic Acids to fertilization programs residues in the huge increase in Cation Exchange Capacity (CEC). Cation Exchange Capacity (CEC) quantifies the ability of a soil to provide a nutrient reserve for plant uptake. In scientific terms CEC is the sum of exchangeable cations (positively charged ions) soil can adsorb per unit weight or volume and is usually measured in milligram equivalents per 100 g. Translated this term means that Humic Acids provide a way of storing the various nutrients (the so called cations of Calcium, Potassium, Magnesium, Nitrate Nitrogen, etc. for absorption by the root system rather than allowing them to travel to the water table below and be lost to be plant. By far the most important ions are the primary nutrients, Nitrate (HN4 +), Phosphorus (P+), and Potassium (K+).

The ammonium ion, the principal source of nitrogen, both as an applied fertilizer as well as from decomposition of various organics (cotton seed meal and alfalfa), requires conversation by various soil bacteriums into the Nitrate ion (NO3-). The retention of Nitrate ions NH4 onto the various + Humic Acids structures via cation exchange allows the conversion to take place for later assimulation by the root structure. While various naturally occurring soils have a low CEC value (0-75), soil humus has the highest levels of all (150-250).

In lay terms, both clay and organic matter have tremendous numbers of negatively charged sites that can hold positively charged ions to their surfaces. This process of grabbing the positive ions is termed as Cation Exchange Capacity (CEC) and provides a reservoir of nutrients close to the root structure. Nutrient ions, once attracted to the various humic acids are then available for rapidly exchange with other soluble ions leading to adsorption through the roots of the plant. The process of altering the pH of an acidic soil by adding lime is illustrated in the diagram.

The preponderance of hydrogen ions (H+) attached to the clay-organic soil particle has resulted in a soil with a pH level well below that required for efficient and rapid nutrient exchange to the roots of the plants. The addition of lime (or the fine powdered dolomite lime) provides a large quantity of Calcium ions (Ca++) and Magnesium ions (Mg++) which readily exchange with the hydrogen ions and the aluminum ions to hereby raise the pH to a satisfactory level for optimum rose growing (pH 6.5 -7.0). (see diagram- yellow box below)

Conclusions

With the proliferation of applied chemical based fertilizers to provide a complete diet of primary, secondary and micro-nutrients to the rose plant, it necessary to also provide a mechanism for efficient transfer of these nutrients to the roots system. Employing an organic aspect to fertilization programs is fundamentally important to exploit fully efficient transmission. There are several ways to accomplish this task.

1. Depend solely on an organic approach knowing that bloom production will not attain that of chemical programs. This option will ensure a good soil via natural processes.

2. Devise a feeding plan that is equally composed of chemical versus organic using such organics as cotton seed meal and alfalfa or other organic base fertilizers.

3. Maintain a 100% chemical program with addition of a good organic mulch and most importantly the regular monthly application of Humic Acid via your composting. This combo of chemical and Humic Acid derived from composting will enhance your rose growing experience.

BENEFITS OF HUMIC ACIDS

Physical Property Changes

1. Very small clay particles called floccules, along with charged organic humic acids form bonds that permit greater stability and persistence within the soil matrix composed of much large aggregates leading to formation of blocks that improve the circulation of water and air around the roots.

2. As organic matter increases, so does soil water holding capacity. The water capacity of humus compared to silicate clay soils is 4 to 5 times.

3. Improves the structure of soil and increases aeration of soil leading to better workability.

4. The darker color imparted leads to greater absorption of solar energy providing warmer sub soil temperatures.

Chemical Changes

1. Serves as a buffer to neutralize both excessive soil acidity and alkalinity ensuring that nutrient ions are not rendered insoluble and unavailable to the plant.

2. Serves to strongly bind aluminum to reduce toxic effects.

3. Improves both the uptake and retention of vital nutrients.

4. Accelerates decomposition of soil minerals.

5. Induces high Cation Exchange Capacity (CEC) ensuring retention of nutrients for later assimilation by root structure.

6. Absorbed cations (the nutrients) attract water molecules for ease of transmission to plant.

Biological Changes

1. Various growth regulators, vitamins, amino acids, auxins, and gibberellins, are formed as organic matter decays just enhancing growth.

2. Stimulates root development

3. Enhances natural resistance against diseases.

4. Stimulates overall plant growth by increasing microbial like by up to 2000 times in just a few weeks.

5. Excellent food source for mycorrhizal fungus.

Tommy Cairns, ‘Soil Science Humus: The Importance of Humic Acid’, Mar/April 2014. Roses 90210, Tommy Cairns, ed. The Beverly Hills Rose Society.

It all starts at the bottom

Those of us who love roses are in our own private nirvana every spring when our first blooms burst forth, as fragrant and perfect as they will ever be. It’s enough to make even the most seasoned gardener forget that most of our rose plants’ labors begin under the ground, in an environment we seldom see. To understand how the importance of roots and the soil around them, it helps to know something about their structure. A root is the first thing to emerge from a seed in its quest for life. The first root from a seed is often a taproot that sprouts finer fibers that grow out into the soil. As the plant grows and develops more roots, some of them undergo secondary growth, becoming woody. The main function of these woody roots is to provide a structure to connect the many, finer roots to the plants. These roots branch out and grow away from the plant, producing fine hairs along their length that absorb large amounts of water and nutrients from the soil. Vascular systems that transmit water, nutrients, and manufactured sugars throughout the plant are contained in a root’s plant tissues.

The maturity of the plant and the density of the soil determine the size of the root structure. Still, despite the size of the entire root system, roots are fragile, particularly the fine roots and root hairs that are the major collectors of water and nutrients. New rose plants are especially vulnerable with their limited systems of young, non-woody roots.

Gardeners have to work directly with a plant’s roots when planting or transplanting it. Transplant shock is a result of damage to root hairs that impedes water absorption until the plant can replace them.

Some shock is unavoidable, but it is important to keep the rootball, a clump of soil that contains many of the roots, together when transplanting. It is helpful to cut the plant’s foliage back, giving the roots time to recover and grow before they have to provide water for a plant with lots of leaves.

A rose bush in a pot can develop such a healthy root system that the roots run out of room in the pot and begin to grow around its edges. The plant suffers as the amount of roots takes up space where water and soil should be. Water runs through the pot and the bush seems to wilt quickly. Repot it into a larger pot or take it out of the pot it is in, trim the roots, add fresh soil, and put it back into the same pot.

Conversely, a small, young rose plant will not do well in a pot that is too large. If the proportion of the soil to the new, tender roots is too high, it will hold too much water for the roots to absorb, making them vulnerable to rot. Young roots are easily crushed when potted too early. Give new plants time to develop roots in their small pots before moving them up to the next pot size.

Other things besides planting and transplanting can harm roots. Chemicals in the soil can inhibit root growth. Parasites, such as nematodes that thrive in warm, sandy soils and diseases are a danger, as are the digging and burying habits of animals. Talk to any rosarian with a gopher problem and they will tell you the horror of pushing on a bush and watching it fall over, completely rootless.

What can a gardener do to increase the health of plant roots? Obviously, the soil around the root is of key importance. Friable soil, that is soil that is loose and crumbly, allows space for air and water. These two elements should make up about 50% of a soil’s content so that roots can find space to grow and microbes, worms, and other soil life can flourish. Roots are directed in their growth by the amounts of water, air, and nutrients available for uptake. Roots will stay away from compacted soil and drown in soil that is not well drained. Healthy soil, with a good balance of water, air, minerals, and life forms will result in fast growing, strong roots.

The best way to improve soil texture and drainage is to add compost. Compost consists of naturally decomposed organic materials. Biological organisms break down these materials into a dense, dark mixture that provides carbon and nitrogen amendments to the soil. Serious gardeners often create compost in their backyards while those who lack time and space for such an endeavor can buy it in bags from a store. The product should be loose and dark brown or black in color with no recognizable wood.

Compost should be moist, not soggy, and if it dries to a light brown color, there is probably too much soil and not enough nutrients. Finally, off odors of ammonia or sulfur indicate that the compost has not decomposed enough. Spread compost over the ground surface and it will work its way down into the soil.

Humic and fulvic acids are products that can improve soil health and increase root vitality. These acids are the end products of the microdegradation of plant matter in soils, composts, peat bogs, and water basins. They are not a fertilizer; rather, they improve the soil by strengthening biological activity and increasing water retention. In addition to these benefits, nutrient uptake is improved and chlorophyll synthesis is increased. Finally, humic acid can chelate micronutrients, breaking ionic bonds and increasing their availability in the soil. Increased soil health results in stronger root growth. Humic acid is available in liquid and dry forms from specialty nurseries.

Other amendments that affect soil composition are gypsum, leaf mold, and manures. Gypsum can loosen clay soil by reacting chemically to the soil’s salts. Leaf mold, shredded composted leaves, also loosens soil and provides organic matter. Manures that are composted are high in nitrogen and other nutrients. However, they also contain salts which may add to the saline content of the soil. Too many salts in the soil can actually draw moisture out of plant roots in a reverse osmosis process.

The addition of mycorrhizae to the soil is a controversial topic for gardeners. This group of fungi develops a symbiotic relationship with plant roots; the roots provide the mycorrhizae with food while the fungi extend the reach of the roots for water and nutrients by attaching to the root and extending long strands of mycelium throughout the soil. Initially rose lovers were enthusiastic about mycorrhizae, but further research has dimmed that enthusiasm. Inoculation of mycorrhizae can be expensive and the exact kind of mycorrhizae that work best with roses is uncertain. Perhaps most illuminating is the research that indicates that the major nutrient a plant gains through mycorrhizae’s increased root capacity is phosphorus. If a plant has enough phosphorus, it doesn’t send out the signals that encourage symbiotic mycorrhizal growth. Adding phosphorus in fertilizer may negate the benefits of any inoculation. Is there a rose lover anywhere who can swear he will never use phosphorus again in fertilizing roses? The money for mycorrhizae would be better invested in a garden wide application of humic acid.

Finally, protect your rose bushes’ roots with a nice two to three inch layer of mulch. This will keep the roots cool and slow down the growth of water stealing weeds. Any roots too close to the soil surface will be cushioned against surface injury. Enjoy the blooms of spring, but don’t forget what lies beneath!

Roses love to grow. Given minimal care they will survive and produce flowers. With a regular feeding program and a varied diet, roses will thrive and produce armloads of large, beautiful blooms. There are many types of fertilizers, liquid (soluble) or dry (granular), organic or in-organic. Find a program that works for you, but do it on a once-a-month basis during the growing season.

ORGANIC VS. IN-ORGANIC: Organic (or natural) fertilizers are derived from any formerly living plant or animal matter. Most commonly used are blood meal, cottonseed meal, bone meal or superphosphate, alfalfa meal and fish meal. Manures – chicken, rabbit and steer are also in this category. Organics are generally slower-release, as they require decomposition by soil micro-organisms before being usable by the plant. They supply benefits to the soil in addition to food for the plants, and should therefore be a regular part of your amendment program.

In-organic (or chemical) plant foods are man-made compositions, formulated for various speeds of release, but generally provide an immediate food source for our heavy-feeding roses, as compared to organic foods. Brand name manufactured rose foods include Bandini , Fertilome , Miracle-Gro , RapidGro , Sterns , Peters , etc. Roses utilize natural and chemical food sources equally, and benefit greatly from use of both, on an alternating basis.

“BALANCED” ROSE FOOD: The term is used frequently, and simply means that a fertilizer has a blend of Nitrogen, Phosphorus, and Potassium (N-P-K), though not necessarily in equal parts, in a formulation beneficial for roses. Nitrogen, Phosphorus and Potassium are the three major ingredients required by all plant materials, in varying proportions, dependent upon the plant s needs. Fertilizers, by law, have a numerical N-P-K ratio printed on the container. A 6-12-6 ratio means that the mixture contains 6% Nitrogen, 12% Phosphorus and 6% Potassium. It contains 24% total nutrients and 76% filler material. 6-12-6 is considered a Balanced Rose Food, as it supplies the basic ingredients in proportions beneficial to roses on a continual basis.

Roses utilize each ingredient at differing times of the growth and blooming cycles. More Nitrogen is needed for early spring growth of stems and foliage, plus continual moderate supply during the entire growing season. Phosphorus is for roots and blooms; a higher phosphorus food should be supplied from 3 weeks before blooming until blooming. Potassium provides health for the plant, a catalyst for Nitrogen and Phosphorus. It also builds in hardiness to heat, drought and cold, and is therefore a good supplement just prior to the dormant season.

Each of the three ingredients may be purchased separately for addition to specialized feedings.

NITROGEN SOURCES When we add organic matter to our soil, its nitrogen content is not immediately available to the plant; it must first be broken down during the decay process. During that process, matter is transformed first into ammonium, then to nitrite, and finally to nitrate nitrogen forms. While the process can take from several days to years, various compounds are formed which are used by soil microorganisms for their own growth.

Since the nitrogen required by rose bushes is mainly in the nitrate form, the importance of chemical fertilizers becomes evident: to supply instantly available nitrogen via nitrate forms; plus nitrogen available within a short space of time via ammonium forms (urea and ammonium phosphates, etc.). A fertilizer containing all three sources – nitrate, ammonium and urea is superior. Learn to read labels to determine nitrogen sources.

PHOSPHORUS AND POTASSIUM Both are supplied as primary nutrients in balanced fertilizers. Phosphorus moves very slowly in the soil, so applications are available only to feeder roots within a few inches of the soil surface. Continued use ensures that a supply of phosphorus will eventually reach the lower root structures, provided the soil Ph is proper. The importance of placing bone meal or superphosphate in the bottom of the planting hole becomes clear – newly planted roses need phosphorus supplied at the root zone. Potassium also moves slowly and is not readily leached from the soil. However, it is extremely mobile within the plant system, where it can be leached from the leaves (its primary destination), by rain or irrigation. A continual supply of potassium is good practice.

SECONDARY- AND MICRO-NUTRIENTS In an effort to provide the ultimate balanced fertilizer for roses, some formulations include secondary nutrients (calcium, magnesium and sulphur, etc.). Sulphur is an excellent ingredient to help acidify alkaline soil. Where soils are acid, additions of Lime will adjust the pH. High calcium content in soils can render magnesium unavailable – another good reason to add Epsom Salts (magnesium sulphate) continually.

Micronutrients (iron, zinc, manganese, copper, cobalt, boron, chlorine and molybdenum) are added in some formulations as well. Percentages are typically small, as roses require only small amounts. Consider a fertilizer with chelated forms of micronutrients as most desirable, as they are the most usable by the plant.

“CHELATED” ELEMENTS (IRON, ZINC, MANGANESE, ETC.) Several trace elements already exist in soils, and are added to fertilizers as an additional supply. If the soil Ph is too high (above 7.0), some elements become unusable (insoluble) by the plant. This is especially true of iron and manganese, and to a lesser degree, copper, zinc and boron.

Chemical reactions in the soil slowly convert the elements into insoluble forms. First, soil Ph must be adjusted to the 6.0 – 7.0 range, then usable forms of the elements must be added. “Chelates”, without getting scientific, are simply forms of each element that remain soluble in the soil, and are readily available to the plant. However, since this solubility allows them to readily move out of the root zone with irrigation, repeated applications are needed.

Hence, the value of a fertilizer with chelated forms of the trace elements included.

This new knowledge of fertilizers is only a basic beginning to understanding the needs of roses. An excellent program to continually acquire new techniques to grow roses is available through a membership in the American Rose Society. The monthly American Rose Magazine is alone worth the low membership fee, and can save you equal amounts in reduced costs through better understanding of how to grow roses!

Soil and water

Soil Pores, Water and Productivity

A productive soil is permeable to water and is able to supply water to plants. A soil’s permeability and water-holding capacity depends on its network of pores:

• Large pores (macropores) control a soil’s permeability and aeration. Macropores include earthworm and root channels. Because they are large, water moves through them rapidly by gravity. Thus, rainfall and irrigation infiltrate into the soil and excess water drains through it.

• Micropores are fine soil pores, typically a fraction of a millimeter in diameter. They are responsible for a soil’s water-holding capacity. Like the fine pores in a sponge or towel. Micropores hold water against the force of gravity. Much of the water held in micropores is available to plants, while some is held so tightly that plant roots cannot use it.

Soil that has a balance of macropores and micropores provides adequate permeability and water-holding capacity for good plant growth. Soils that contain mostly macropores drain readily, but are droughty and need more frequent irrigation. Soils that contain mostly micropores have good water-holding capacity but take longer to dry out and warm up in the spring. Runoff of rainfall and irrigation water also is more likely on these soils.

What Affects Soil Porosity?

Several soil properties affect porosity, including texture, structure, compaction and organic matter. You can evaluate your garden soil with respect to these properties to understand how they affect its porosity. The only tools you need are your eyes, fingers and a shovel.

Clay particles are the smallest — about the size of bacteria and viruses — and can be seen only with a microscope. They typically have a flat shape, similar to a sheet of mica. Soils rich in clay feel very hard when dry, but are easily shaped and molded when moist. Although all of these particles seem small, the relative difference in their sizes is quite large. If a typical clay particle were the size of a penny, a sand particle would be as large as a house.

Soil texture directly affects porosity. Pores between sand particles tend to be large, while those between silt and clay particles tend to be small. Thus, sandy soils contain mostly macropores and usually have rapid permeability but limited water holding capacity. Micropores predominate in soils containing mostly silt and clay, creating high water holding capacity but reducing permeability.

Particle size also affects the surface area in a volume of soil. Surface area is important because surfaces are the most active part of the soil. They hold plant nutrients, bind contaminants and provide a home for microorganisms. Clay particles have a large surface area relative to their volume, and a small amount of clay makes a large contribution to a soil’s surface area.

Nearly all soils contain a mixture of particle sizes and have a pore network containing a mixture of pore sizes. A soil with roughly equal influence from sand, silt and clay particles is called a loam. Loams usually make good agricultural and garden soils because they have a balance of macropores and micropores. Thus, they usually have good water-holding capacity and moderate permeability.

A sandy loam is similar to a loam, except that it contains more sand. It feels gritty, yet has enough silt and clay to hold together in your hand. Sandy loams usually have low to moderate water-holding capacity and good permeability. Silt loams are richer in silt and feel smooth rather than gritty. They are pliable when moist, but not very sticky. Silt loams usually have high water-holding capacity and low to moderate permeability.

Clays and clay loams are very hard when dry, sticky when wet and can be molded into wires and ribbons when moist. They generally have high water-holding capacity and low permeability. Almost any texture of soil can be suitable for gardening, as long as you are aware of its limitations and adjust your management to compensate. Clay soils hold a lot of water, but are hard to dig and dry slowly in the spring. Sandy soils need more frequent watering and lighter, more frequent fertilization, but you can plant them earlier in the spring. All soils can benefit from additions of organic matter, as described below under “Adding Organic Matter.”

Many soils contain coarse fragments, such as gravel and rocks. Coarse fragments do not contribute to a soil’s productivity and can be a nuisance when you are digging. Don’t feel compelled to remove them all from your garden, however. Coarse fragments aren’t harmful, and your time is better spent doing other gardening tasks. The only time rocks are a problem is when you have nothing but rocks on your land. Then, water and nutrient-holding capacities are so low that it is difficult to grow healthy plants.

Clay — The smallest type of soil particle (less than 0.002-mm in diameter).

Sand — The coarsest type of soil particle (0.05- to 2-mm in diameter).

Silt — A type of soil particle that is intermediate in size between sand and clay (0.002- to 0.05-mm in diameter).

Soil — A natural, biologically active mixture of weathered rock fragments and organic matter at the earth’s surface.

Growing roses is more than just digging a hole in the ground and sticking a rose into it and expect to have great roses. Knowing and understanding the importance of soils and fertilizers is very important to growing roses and other plants.

Soil texture

Texture describes how coarse or fine a soil is. The coarsest soil particles are sand. They are visible to the eye and give soil a gritty feel. Silt particles are smaller than sand — about the size of individual particles of white flour. They give soil a smooth, floury feel. On close inspection, sand and silt particles look like miniature rocks.

Soil Structure

Percentages of clay, silt, and sand in the basic soil textural classes

Individual particles of sand, silt and clay tend to cluster and bind together, forming aggregates called peds, which provide structure to a soil. Dig up a piece of grass sod and examine the soil around the roots. The granules of soil clinging to the roots are examples of peds. They contain sand, silt, clay and organic matter. Aggregation is a natural process caused largely by biological activity such as earthworms burrowing, root growth and microbial action. Soil organic matter is an important binding agent that stabilizes and strengthens peds.

The spaces between peds are a soil’s macropores, which improve permeability, drainage and recharge of air into the soil profile. The pores within peds are predominantly micropores, contributing to the soil’s water-holding capacity. A well-structured soil is like a sponge, allowing water to enter and soak into the micropores and letting excess water drain downward through the macropores. Good structure is especially important in medium to fine textured soils, because it increases the soil’s macroporosity, thus improving permeability and drainage.

Compacted soil resists root penetration and water movement.

Compaction and Loss of Structure

Soil structure is fragile and can be damaged or destroyed by compaction, excessive tillage or tillage when the soil is too wet. Loss of organic matter also weakens structure. Compaction squeezes macropores into micropores and creates horizontal aggregates that resist root penetration and water movement. Compaction often occurs during site preparation or house construction, creating a difficult environment for establishing plants. Protect your soil from compaction by avoiding unnecessary foot or machine traffic. Tilling when soil is too wet also damages soil structure. If you can mold a piece of soil into a wire or worm in your hand, it is too wet to till. If the soil crumbles when you try to mold it, it is dry enough to till.

Compacted soil resists root penetration and water movement. Structural damage caused by human activity usually is most severe within the top foot of soil and can be overcome by proper soil management. In some soils, there is deeper compaction resulting from pressure from ancient glaciers. Glacially compacted subsoils (a type of hardpan) are common in the Puget Sound area, where the compacted layer often begins 18- to 36-inches below the soil surface. Where the land surface has been cut, leveled or shaped for development, the compacted layer may be much closer to the surface. This layer looks like concrete and is so dense and thick that it is nearly impossible to work with. If your garden has a glacially compacted layer close to the soil surface, consider using raised beds to increase soil depth.

Organic Matter

Adding organic matter is the best way to improve the environment for plants in nearly all soils. Organic matter helps build and stabilize soil structure in fine-textured and compacted soils, thus improving permeability and aeration and reducing the risk of runoff and erosion. When organic matter decomposes, it forms humus, which acts as a natural glue to bind and strengthen soil aggregates. Organic matter also helps sandy soils hold water and nutrients. See “Adding Organic Matter” later in this chapter for information on amending soil with organic matter.

Slope, Aspect, Depth and Water

Slope, aspect (direction of exposure) and soil depth affect water availability and use in a soil. Choose plants that are best suited to conditions on your property. Ridge tops and side slopes tend to shed water, while soils at the bottoms of slopes and in low areas collect water. Often, soils that collect water have high winter water tables, which can affect the health of some plants. Soils on ridge tops are more likely to be droughty. Site aspect also is important. South- and southwest- facing exposures collect the most heat and use the most water.

Soil depth also affects water availability by determining the rooting zone. Soil depth is limited by compacted, cemented, or gravelly layers, or by bedrock. A shallow soil has less available water simply because the soil volume available to roots is smaller. Dig below the topsoil in your garden. The deeper toucan dig before hitting a restrictive layer, the greater the soil volume for holding water.

Water Management in Your Garden

Soils and Irrigation

Most gardens in the Northwest require summer irrigation. Themed for irrigation varies, depending on soil water-holding capacity, weather, site aspect, the plants grown and their growth stage. In most cases, the goal of irrigation is to recharge the available water in the top foot or so of soil. For sandy soil, 1-inch of irrigation water is all you need. Any more will leach (move downward) through the root zone, carrying nutrients with-it. A silt loam or clay soil can hold more than 2-inches of water, but you may need to irrigate more slowly to prevent runoff.

Wet Soils

If your soil stays wet in the spring, you will have to delay tilling and planting. Working wet soil can damage its structure, and seeds are less likely to germinate in cold, wet soil. Some plants don’t grow well in wet soil. Raspberries, for example, often become infected by root diseases in wet soil and lose vigor and productivity. A soil’s color gives clues to its tendency to stay wet. If subsoil is brown or reddish, the soil probably is well drained and has few wetness problems. Gray subsoils, especiallythose with brightly colored mottles, often are wet. If your soil is gray and mottled directly beneath the topsoil, it probably is saturated during the wet season. Sometimes, simple actions can reduce soil wetness problems. For example:

• Divert runoff from roof drains away from your garden.

• Avoid plants that perform poorly in wet conditions.

• Use raised beds for perennials that require well-drained soil and for early-season vegetables.

Investigate whether a drain on a slope will remove excess water in your situation. Installing drainage can be expensive, however. When considering drainage, make sure there is a place to drain the water. Check with local regulatory agencies to see whether there are restrictions on the project.

Craig Cogger (cogger@wsu.edu), ‘Guide to Soil and Fertilizer, Parts I & II’, March & April 2014. Thorny Issues. Dan Simmons (puyalluprose@comcast.net), ed. Puyallup Rose Society