SOIL MANAGEMENT
Are your roses growing as well as they can? There may be many reasons why they are not performing as they should. Some problems have simple solutions, while others are a bit more complex. Many are physiological and have no relation to an infectious disease or plant pests. Most arise from problems with the plant's environment, such as the soil. Too much or too little water, poor drainage, insufficient soil aeration, or a nutrient deficiency, etc. may be the cause. These are conditions that need to be identified and eliminated in order to grow healthy roses.
It is a well known fact that insects and diseases thrive on stressed and unhealthy plants with little resistant. Start with a biologically active soil rich in humus. Under the proper conditions of moisture and soil temperature, most species of soil organisms in the process of decomposition produce various substances such as antibiotics, enzymes and trace elements, that while providing optimal plant growth, also help fight off diseases, resulting in a natural immunity for the plants, before insects and diseases can get established.
Not all of the problems related to unhealthy plants are caused by environmental conditions. Some of the problems can be traced to various insects that inhabit the soil, such as nematodes and fungus gnats , etc. They can feed on the plant's roots and can spread diseases showing symptoms similar to that of plant dehydration, and yet not be caused by a lack of moisture in the soil.
While everyone agrees that water is of the utmost importance for growing roses, so is proper soil management. Part of this ‘management' is the conserving of soil moisture for as long as possible, by any and all means. The best method of conserving moisture is by incorporating organics regularly, like sphagnum peat moss, or compost, to build up a live healthy soil. This results in improved soil aeration and moisture retention, as well as improving the tilth (workability) of the soil. Opening up the soil for greater air infiltration makes for quicker decomposition of organic matter. This organic material feeds the soil's active microorganisms as it decomposes, thereby building the soil structure, insuring a constant supply of nutrients and humus, which acts as a reservoir for storing soil moisture.
During hot, dry periods, with a breeze, the loss of moisture will be greatly increased. Having a limited root system and large top growth during these hot dry periods caused some plants to dry out quickly. Plants sometimes lose more moisture through the leaves than the roots are able to absorb from the soil, causing a temporary wilting of the foliage . Water along with dissolved nutrients are pulled upward by capillary action under tension. Moisture flows from the roots through the xylem tubes to the leaves, where it evaporates into the atmosphere ( leaf transpiration ), producing a cooling effect in hot weather. As long as the capillary action remains unobstructed, the plant receives an adequate supply of water. Problems can arise when planting a potted plant in a soil that is not compatible, resulting in a break in the continuity of gravity's pull of water by the roots.
Soil is the key to growing healthier roses. A garden soil is nothing more than a combination of rocks worn down over the years by nature into various sized particles from silt to coarser sand to very fine sand and combined with a sufficient amount of organic matter, such as peat moss, decayed leaves, etc.
There are basically 12 recognized types of soil structures that make up the physical structure of a soil, with the percentage of sand, silt, and clay determining the class. These are light, medium, and heavy soils, depending on the degree of air infiltration, water, and nutrient absorption. A basic formula is 1/3 coarse sand, 1/3 clay, and 1/3 decomposed organic matter. When mixed together, they provide a soil mixture that is light and friable, doing what you want it to do. This is known as loam , and is what you should try to change your existing soil to if need be.
A light soil is generally sandy. While it provides excellent drainage and aeration, and has the ability to warm up quickly in the spring, it is often on the acid side, and lacks the ability to retain moisture or nutrients. To overcome these problems, a large amount of organic matter needs to be worked into this kind of soil.
The soil structure in many parts of the mid-west is clay or silty clay loam, a heavy soil. This makes it ideal for its ability to absorb and retain moisture and nutrients, but it suffers from poor drainage . To correct the drainage problem of a heavy soil ( which you must do to get oxygen down into the root system ), you must work in coarse sand (torpedo) and decomposed organic materials.
Thus it becomes very apparent that a medium type of soil structure is best. One which incorporates only the best features of clay soils and sandy soils into one that is fertile , (necessary nutrients available in the soil) and well balanced.
Any soil can be conditioned into one that will produce good roses by incorporating into it what the soil is lacking. Do not try to condition a soil that is too wet to work. All you will do is compact it, making it extremely difficult to condition afterwards. Fall is often the best time to condition the soil , as there is still sufficient time to incorporate anything that is required to improve the soil, letting it mellow over the winter months for next year's spring growth.
Soil aeration is necessary in order for the soil's micro-organisms to function properly. This is vital in the utilization of plant fertilizer as the micro-organisms feed on the organic matter as they condition the soil. Over a period of time this organic matter is depleted, and needs to be replenished. The more chemical fertilizer used, the quicker this will happen. For this reason, it is a good practice to incorporate some organic matter into the soil every year . Without these organisms and enough organic matter for them to feed on, any fertilizer you give your plants will be of little value.
You should have a professional soil test made at least every four years, sooner if there are problems with the roses. During the growing season, check the soil's pH yourself. There are soil testing kits and meters available that are easy to use. Even though there are indications that the soil is lacking in a certain element, the element may be present in the soil, but because it is locked up in the soil by a pH too high or too low, it is unavailable to the plant. Adding fertilizer to a plant suffering poor growth is of little use, unless the soil is first conditioned to a level where the plant can take up and utilize the available nutrients.
The pH in a soil is commonly referred to as the acidity/alkalinity balance. On a scale of 0 to 14, 7 is neutral. Above seven is alkaline, below seven is considered acid. In many parts of the mid-west the soil is on the alkaline side ; that is … one containing too much calcium and sodium. Having a soil on the alkaline side, 7.0 and above, the phosphorous in the soil combines with the calcium forming an insoluble calcium-phosphorous compound making this element unusable to the plant until the pH is lowered. For roses the pH range should be in between 6.0 and 7.0, with 6.5 being ideal.
Sulfur is usually used to lower the soil's pH, while dolomite lime is used to raise it. Dolomite lime is also a source of calcium and magnesium. The quantity to use to raise or lower the pH to the desirable range is on the box. Claims are made by many rosarians that Epsom Salts ( magnesium sulfate ) agricultural grade encourages basal breaks. There is a great percentage of Sulfur (S) (12.9%) and Magnesium (Mg) (9.8%) in a 50# bag. If you already have a soil on the acid side, adding Sulfur will lower your pH further! Be wary of the ashes from some types of briquettes used for outdoor cooking. While many are a source of Potash , some contain a high level of Sulfur. This, when combined with water, forms sulfuric acid, which will again lower the pH of your soil.
Gypsum ( calcium sulfate ) does not change the soil's pH and has the ability to loosen up a heavy clay soil. Soils high in excessive amounts of sodium salts sustain damage to their structure. Having an alkaline condition can cause the plant leaves to burn. Adding gypsum provides calcium that replaces the sodium in the soil's structure. This breaks the sodium's bond allowing water to flush out the soil's salt build-up from too much chemical fertilizer.
It is important that you understand the relationship between water, soil, and maintaining the proper soil pH. Make adjustments if need be, and when the new rose season is in full swing, take inventory of how the roses are performing in this changed environment. If the roses are still not up to your expectations, what are the problems? Is new growth stunted and puny looking, or are blooms or foliage of abnormal size? Do you have healthy looking foliage, but no flower buds? How about the color of the blooms; are they washed out and faded looking, instead of deep vivid colors? Are leaves a lime green or yellowish ( chlorotic ) color instead of the dark green which is normally associated with healthy foliage? Maybe something is missing or not being utilized in the soil.
There are times when a plant may show some signs of a nutrient deficiency even after being fertilized. These are lack of color in the blooms, plants are stunted, some leaves turn light green, white, dull gray, yellow etc. All these symptoms can be caused by a lack of one or more trace elements (not all fertilizers contain trace elements). A trace element can provide a plant and the soil bacteria with a balanced nutrition. When using a trace element, only a very small quantity is necessary.
An example of a nutrient deficiency: when the trace elements are used up in the soil, the leaf turns yellow while the veins of the leaf remain green.
This condition usually occurs when there isn't enough magnesium in the soil, which the plant uses to manufacture chlorophyll. Yellow leaves (chlorotic) are a good indication that the plant has some type of a physiological problem, a nutrient deficiency, or a problem with the plant's environment.
While there are many reasons that cause leaves to yellow, their symptoms can be confusing; often it looks like it could be from a shortage of several different elements.
A nutrient deficient plant is plagued by insects and diseases more often than a healthy plant. It has been reported in Britain's RNRS Journal that there is a direct relationship between blackspot and the imbalance of nutrients in the plant. Fertilizer venders are advertising the use of sulfur and other trace elements in controlling blackspot. ( NOTE : Keep in mind that Sulfur also lowers the pH of the soil.)
Nature provides the sunshine, air, and water for the plant to grow. For optimum growth, the plant requires food in the form of Nitrogen, Phosphorous, and Potassium (N P K), plus smaller quantities of minor trace elements that are generally available in a properly conditioned soil. Your fertilizer supplies all these elements, and most are always listed on the bag, along with the trace elements if it contains any.
Fertilizers are water soluble or found in a time-release granule. There are many time-release chemical fertilizers (inorganic) available, which provide nutrients to the soil for 3 months, 6 months, etc. All work harmoniously with existing soil organics encouraging better plant growth. As the soil temperature warms (to 40 degrees F.), nutrients are released. As days become warmer and the soil temperature increases, more of the nutrients are released. Using the 3-month type of granules where the weather is hot, there may not be a sufficient supply of nutrients to last the entire summer.
Chemical fertilizers: are expressed as a percentage of each of the primary nutrients in the bag. A 100# bag of 15-30-15 has 15% of nitrogen, 30% available phosphate, and 15% of potassium (soluble Potash). Some fertilizers (special purpose) can contain only one or two of the primary elements. Nitrogen is used for green, denser foliage. Available Phosphate is associated with the flower, and soluble Potash is for the plant's hardiness. A balanced fertilizer that contains both major and minor (trace) elements works well for general use. A plant cannot tell the difference between a package labeled as a rose fertilizer or labeled as a grass fertilizer; the numbers are what count. The same with the amount of fertilizer used, if you normally give a plant two tablespoons of 10-10-10, and the package you are now using is 20-20-20, use only one tablespoon. Use only the amount called for. Using too much of one element can cause a reduction in another.
In early spring, plants require a bit more of a slow release nitrogen fertilizer such as Nitroform blue chip 38-0-0, than during the growing season. For this you can use a balanced fertilizer like Envy 20-20-20. In late fall, or eight weeks prior to the application of winter protection, no fertilizer is put into the soil, except maybe a hand full potassium worked into the soil around each bush. Use 0-0-20 (one without nitrogen), as this helps the plant harden canes for the winter.
Organic fertilizers are not the quickest way to get nutrients into the soil; the organic matter must first be converted into a chemical before the plant can utilize it. Having a soil high in organic matter does permit a greater quantity of chemical fertilizer can be added. While manure is good fertilizer, it requires addition of a great quantity if the primary use is for its nitrogen content. Alfalfa, being organic, releases nutrients slowly and continuously after the soil has warmed (60 degrees F.). Plants start feeding as it decomposes in the soil, releasing its nutrients to the root system whenever water is applied. Alfalfa forms a compound that, while improving the plant's vigor, produces healthier and greener foliage and brighter colored blooms, as well as new basal breaks. The same may be said for using fish and liquid seaweed with your fungicide spray on the roses. I personally believe they help keep plants free of many plant pests and diseases. Being organic these are not likely to burn a plant's roots.
Foliar feeding (fertilizing through the leaves) - utilization of most nutrients (NPK) applied to the foliage is many times greater than if applied to the soil. As for minor nutrients (trace elements) the utilization is even higher. If you foliar feed, you can combine a foliar fertilizer with your fungicide spray solution (if they are compatible), for as long as you continue to spray. These fertilizers can be a balanced one containing all three major elements. In no way will foliar feeding in the late fall affect the normal process of the plant going dormant.
Adding a fertilizer before you know the soil's requirements may do more harm than good. DANGER: great care should to taken when adding a fertilizer high in nitrogen (like Urea 46-0-0) as this can burn the fine feeder roots, ultimately resulting in foliage becoming parched, brown or black. This is especially true with miniatures, since they require much less fertilizer.
Too much Nitrogen is also associated with rose plants having a lot foliage, but no blooms. Using an excess amount of nitrogen will quickly use up much of the humus in the soil. Whatever type of fertilizer you use, it is very important that the soil is watered before and after a fertilizer is applied.
To summarize all of the above in a few words, to grow healthy roses you need a healthy soil. Use common sense, whatever else is required. What has been advocated in this article is what I try to follow, having learned much from the many mistakes made growing roses for the last thirty-eight years.
It is a well known fact that insects and diseases thrive on stressed and unhealthy plants with little resistant. Start with a biologically active soil rich in humus. Under the proper conditions of moisture and soil temperature, most species of soil organisms in the process of decomposition produce various substances such as antibiotics, enzymes and trace elements, that while providing optimal plant growth, also help fight off diseases, resulting in a natural immunity for the plants, before insects and diseases can get established.
Not all of the problems related to unhealthy plants are caused by environmental conditions. Some of the problems can be traced to various insects that inhabit the soil, such as nematodes and fungus gnats , etc. They can feed on the plant's roots and can spread diseases showing symptoms similar to that of plant dehydration, and yet not be caused by a lack of moisture in the soil.
While everyone agrees that water is of the utmost importance for growing roses, so is proper soil management. Part of this ‘management' is the conserving of soil moisture for as long as possible, by any and all means. The best method of conserving moisture is by incorporating organics regularly, like sphagnum peat moss, or compost, to build up a live healthy soil. This results in improved soil aeration and moisture retention, as well as improving the tilth (workability) of the soil. Opening up the soil for greater air infiltration makes for quicker decomposition of organic matter. This organic material feeds the soil's active microorganisms as it decomposes, thereby building the soil structure, insuring a constant supply of nutrients and humus, which acts as a reservoir for storing soil moisture.
During hot, dry periods, with a breeze, the loss of moisture will be greatly increased. Having a limited root system and large top growth during these hot dry periods caused some plants to dry out quickly. Plants sometimes lose more moisture through the leaves than the roots are able to absorb from the soil, causing a temporary wilting of the foliage . Water along with dissolved nutrients are pulled upward by capillary action under tension. Moisture flows from the roots through the xylem tubes to the leaves, where it evaporates into the atmosphere ( leaf transpiration ), producing a cooling effect in hot weather. As long as the capillary action remains unobstructed, the plant receives an adequate supply of water. Problems can arise when planting a potted plant in a soil that is not compatible, resulting in a break in the continuity of gravity's pull of water by the roots.
Soil is the key to growing healthier roses. A garden soil is nothing more than a combination of rocks worn down over the years by nature into various sized particles from silt to coarser sand to very fine sand and combined with a sufficient amount of organic matter, such as peat moss, decayed leaves, etc.
There are basically 12 recognized types of soil structures that make up the physical structure of a soil, with the percentage of sand, silt, and clay determining the class. These are light, medium, and heavy soils, depending on the degree of air infiltration, water, and nutrient absorption. A basic formula is 1/3 coarse sand, 1/3 clay, and 1/3 decomposed organic matter. When mixed together, they provide a soil mixture that is light and friable, doing what you want it to do. This is known as loam , and is what you should try to change your existing soil to if need be.
A light soil is generally sandy. While it provides excellent drainage and aeration, and has the ability to warm up quickly in the spring, it is often on the acid side, and lacks the ability to retain moisture or nutrients. To overcome these problems, a large amount of organic matter needs to be worked into this kind of soil.
The soil structure in many parts of the mid-west is clay or silty clay loam, a heavy soil. This makes it ideal for its ability to absorb and retain moisture and nutrients, but it suffers from poor drainage . To correct the drainage problem of a heavy soil ( which you must do to get oxygen down into the root system ), you must work in coarse sand (torpedo) and decomposed organic materials.
Thus it becomes very apparent that a medium type of soil structure is best. One which incorporates only the best features of clay soils and sandy soils into one that is fertile , (necessary nutrients available in the soil) and well balanced.
Any soil can be conditioned into one that will produce good roses by incorporating into it what the soil is lacking. Do not try to condition a soil that is too wet to work. All you will do is compact it, making it extremely difficult to condition afterwards. Fall is often the best time to condition the soil , as there is still sufficient time to incorporate anything that is required to improve the soil, letting it mellow over the winter months for next year's spring growth.
Soil aeration is necessary in order for the soil's micro-organisms to function properly. This is vital in the utilization of plant fertilizer as the micro-organisms feed on the organic matter as they condition the soil. Over a period of time this organic matter is depleted, and needs to be replenished. The more chemical fertilizer used, the quicker this will happen. For this reason, it is a good practice to incorporate some organic matter into the soil every year . Without these organisms and enough organic matter for them to feed on, any fertilizer you give your plants will be of little value.
You should have a professional soil test made at least every four years, sooner if there are problems with the roses. During the growing season, check the soil's pH yourself. There are soil testing kits and meters available that are easy to use. Even though there are indications that the soil is lacking in a certain element, the element may be present in the soil, but because it is locked up in the soil by a pH too high or too low, it is unavailable to the plant. Adding fertilizer to a plant suffering poor growth is of little use, unless the soil is first conditioned to a level where the plant can take up and utilize the available nutrients.
The pH in a soil is commonly referred to as the acidity/alkalinity balance. On a scale of 0 to 14, 7 is neutral. Above seven is alkaline, below seven is considered acid. In many parts of the mid-west the soil is on the alkaline side ; that is … one containing too much calcium and sodium. Having a soil on the alkaline side, 7.0 and above, the phosphorous in the soil combines with the calcium forming an insoluble calcium-phosphorous compound making this element unusable to the plant until the pH is lowered. For roses the pH range should be in between 6.0 and 7.0, with 6.5 being ideal.
Sulfur is usually used to lower the soil's pH, while dolomite lime is used to raise it. Dolomite lime is also a source of calcium and magnesium. The quantity to use to raise or lower the pH to the desirable range is on the box. Claims are made by many rosarians that Epsom Salts ( magnesium sulfate ) agricultural grade encourages basal breaks. There is a great percentage of Sulfur (S) (12.9%) and Magnesium (Mg) (9.8%) in a 50# bag. If you already have a soil on the acid side, adding Sulfur will lower your pH further! Be wary of the ashes from some types of briquettes used for outdoor cooking. While many are a source of Potash , some contain a high level of Sulfur. This, when combined with water, forms sulfuric acid, which will again lower the pH of your soil.
Gypsum ( calcium sulfate ) does not change the soil's pH and has the ability to loosen up a heavy clay soil. Soils high in excessive amounts of sodium salts sustain damage to their structure. Having an alkaline condition can cause the plant leaves to burn. Adding gypsum provides calcium that replaces the sodium in the soil's structure. This breaks the sodium's bond allowing water to flush out the soil's salt build-up from too much chemical fertilizer.
It is important that you understand the relationship between water, soil, and maintaining the proper soil pH. Make adjustments if need be, and when the new rose season is in full swing, take inventory of how the roses are performing in this changed environment. If the roses are still not up to your expectations, what are the problems? Is new growth stunted and puny looking, or are blooms or foliage of abnormal size? Do you have healthy looking foliage, but no flower buds? How about the color of the blooms; are they washed out and faded looking, instead of deep vivid colors? Are leaves a lime green or yellowish ( chlorotic ) color instead of the dark green which is normally associated with healthy foliage? Maybe something is missing or not being utilized in the soil.
There are times when a plant may show some signs of a nutrient deficiency even after being fertilized. These are lack of color in the blooms, plants are stunted, some leaves turn light green, white, dull gray, yellow etc. All these symptoms can be caused by a lack of one or more trace elements (not all fertilizers contain trace elements). A trace element can provide a plant and the soil bacteria with a balanced nutrition. When using a trace element, only a very small quantity is necessary.
An example of a nutrient deficiency: when the trace elements are used up in the soil, the leaf turns yellow while the veins of the leaf remain green.
This condition usually occurs when there isn't enough magnesium in the soil, which the plant uses to manufacture chlorophyll. Yellow leaves (chlorotic) are a good indication that the plant has some type of a physiological problem, a nutrient deficiency, or a problem with the plant's environment.
While there are many reasons that cause leaves to yellow, their symptoms can be confusing; often it looks like it could be from a shortage of several different elements.
A nutrient deficient plant is plagued by insects and diseases more often than a healthy plant. It has been reported in Britain's RNRS Journal that there is a direct relationship between blackspot and the imbalance of nutrients in the plant. Fertilizer venders are advertising the use of sulfur and other trace elements in controlling blackspot. ( NOTE : Keep in mind that Sulfur also lowers the pH of the soil.)
Nature provides the sunshine, air, and water for the plant to grow. For optimum growth, the plant requires food in the form of Nitrogen, Phosphorous, and Potassium (N P K), plus smaller quantities of minor trace elements that are generally available in a properly conditioned soil. Your fertilizer supplies all these elements, and most are always listed on the bag, along with the trace elements if it contains any.
Fertilizers are water soluble or found in a time-release granule. There are many time-release chemical fertilizers (inorganic) available, which provide nutrients to the soil for 3 months, 6 months, etc. All work harmoniously with existing soil organics encouraging better plant growth. As the soil temperature warms (to 40 degrees F.), nutrients are released. As days become warmer and the soil temperature increases, more of the nutrients are released. Using the 3-month type of granules where the weather is hot, there may not be a sufficient supply of nutrients to last the entire summer.
Chemical fertilizers: are expressed as a percentage of each of the primary nutrients in the bag. A 100# bag of 15-30-15 has 15% of nitrogen, 30% available phosphate, and 15% of potassium (soluble Potash). Some fertilizers (special purpose) can contain only one or two of the primary elements. Nitrogen is used for green, denser foliage. Available Phosphate is associated with the flower, and soluble Potash is for the plant's hardiness. A balanced fertilizer that contains both major and minor (trace) elements works well for general use. A plant cannot tell the difference between a package labeled as a rose fertilizer or labeled as a grass fertilizer; the numbers are what count. The same with the amount of fertilizer used, if you normally give a plant two tablespoons of 10-10-10, and the package you are now using is 20-20-20, use only one tablespoon. Use only the amount called for. Using too much of one element can cause a reduction in another.
In early spring, plants require a bit more of a slow release nitrogen fertilizer such as Nitroform blue chip 38-0-0, than during the growing season. For this you can use a balanced fertilizer like Envy 20-20-20. In late fall, or eight weeks prior to the application of winter protection, no fertilizer is put into the soil, except maybe a hand full potassium worked into the soil around each bush. Use 0-0-20 (one without nitrogen), as this helps the plant harden canes for the winter.
Organic fertilizers are not the quickest way to get nutrients into the soil; the organic matter must first be converted into a chemical before the plant can utilize it. Having a soil high in organic matter does permit a greater quantity of chemical fertilizer can be added. While manure is good fertilizer, it requires addition of a great quantity if the primary use is for its nitrogen content. Alfalfa, being organic, releases nutrients slowly and continuously after the soil has warmed (60 degrees F.). Plants start feeding as it decomposes in the soil, releasing its nutrients to the root system whenever water is applied. Alfalfa forms a compound that, while improving the plant's vigor, produces healthier and greener foliage and brighter colored blooms, as well as new basal breaks. The same may be said for using fish and liquid seaweed with your fungicide spray on the roses. I personally believe they help keep plants free of many plant pests and diseases. Being organic these are not likely to burn a plant's roots.
Foliar feeding (fertilizing through the leaves) - utilization of most nutrients (NPK) applied to the foliage is many times greater than if applied to the soil. As for minor nutrients (trace elements) the utilization is even higher. If you foliar feed, you can combine a foliar fertilizer with your fungicide spray solution (if they are compatible), for as long as you continue to spray. These fertilizers can be a balanced one containing all three major elements. In no way will foliar feeding in the late fall affect the normal process of the plant going dormant.
Adding a fertilizer before you know the soil's requirements may do more harm than good. DANGER: great care should to taken when adding a fertilizer high in nitrogen (like Urea 46-0-0) as this can burn the fine feeder roots, ultimately resulting in foliage becoming parched, brown or black. This is especially true with miniatures, since they require much less fertilizer.
Too much Nitrogen is also associated with rose plants having a lot foliage, but no blooms. Using an excess amount of nitrogen will quickly use up much of the humus in the soil. Whatever type of fertilizer you use, it is very important that the soil is watered before and after a fertilizer is applied.
To summarize all of the above in a few words, to grow healthy roses you need a healthy soil. Use common sense, whatever else is required. What has been advocated in this article is what I try to follow, having learned much from the many mistakes made growing roses for the last thirty-eight years.
