Our topic for discussion this evening is an all season fertilizer program for growing roses. Before we get into the discussion of the actual fertilizer plan, we need to talk about some fertilizer basics. There is no better place to start than the definition of the word fertilizer. The word has its origins in the Latin word fertilis which means "to bear." According to the dictionary, fertilizer is a noun which derives from the word fertile which botanically means "rich in material needed to sustain plant growth."  Today when we use the word fertilizer it means "any of a large number of natural and synthetic materials spread on the ground or worked into the soil to increase its fertility." Please note the use of the words "natural" and "synthetic."

In order for the fertilizers we put down in our gardens to be effective, certain environmental conditions must be present. It is assumed that the soil is friable and well drained and the garden is located where it can get at least 6 hours of sunlight each day. We also assume that the soil pH is around 6.5. A slightly acid soil condition is considered ideal for roses as all the nutrients will be available in solution for uptake by your roses. It is recommended that you periodically get a soil test to determine the structure of your soil and the pH level. Having this knowledge will give you a starting point for a good fertilizer program.

Food for Thought (and Roses!)

Roses are living things and fertilizers provide the nutrients (food) they need to survive. Some nutrients are required in greater quantities are called "macro" elements. The nutrients that are required in lesser quantities are called "micro" nutrients.

The "macro" elements and their value to the rose are as follows:

1.    Nitrogen - Tall strong canes, blooms, and dark green foliage.
2.    Phosphorus - Root growth, quality plants, and big blooms.
3.    Potassium - Root growth and bloom color.
4.    Sulfur - Plant health. Lowers soil pH.
5.    Calcium - Cell wall development. Sturdier plants.
6.    Magnesium - Chlorophyll formation and healthy plants.

The "micro" elements and the value to the rose are as follows:

1.    Iron - Chlorophyll formation and nitrogen fixation.
2.    Manganese - Chlorophyll and photosynthesis.
3.    Boron - Cell formation and movement of sugars between cells.
4.    Zinc - Stem development and bud formation.
5.    Copper - Vitamin A, stem development and pigment.
6.    Molybdenum - Stimulates plant growth.

Although very important elements, I have not mentioned carbon, hydrogen and oxygen because these elements are available from air and water. Now that we have learned the elements needed by roses for good growth, how do we supply these nutrients to our roses?

Fertilizers

Chemical fertilizers or inorganic fertilizers are man made and are manufactured in well balanced elemental formulations. The inorganic elements of chemical fertilizers are quick-acting and are readily available food for the plants. Most commercial fertilizers contain the three main nutrients needed for good plant growth. They are nitrogen, phosphorus, and potassium. Unless you know the exact levels of nutrients in you garden soil, always use a balanced chemical fertilizer. Many of these formulations also contain the micro nutrients.

One thing is certain about the use of chemical fertilizers, exclusive use can impoverish the soil. Heavy application of chemical fertilizers is only safe when the soil is rich in humus or organic material. In early spring when the soil is cool and there is very little microbial activity, chemical fertilizers provide nutrients in a readily available form. It is better to use small amounts often rather than large amounts all at one time. As the soil temperatures rise, the addition of organic matter is very beneficial.

Urea, a synthetic organic fertilizer, is often used to give roses a boost. The nitrogen content can be as high as 48%. Caution is advised in the use of this product. I use it more to replace nitrogen used up in the decomposition of organic materials than as a fertilizer for a specific plant. Anytime chemical fertilizers are used make sure the soil has plenty of moisture. Never fertilize dry soil. If the fertilizer bag has the initials W.I.N., it is a slow release nitrogen meaning that it must be broken by chemical or microbial action before it can be used by the plant. Water soluble nitrogen (W.S.N.) dissolves in water and is readily available to the plant.

Slow release fertilizers come in three forms: materials that dissolve slowly, materials from which the nitrogen is released by soil micro-organisms, and granular materials with coatings to control the release of the fertilizer. Slow release fertilizers need not be applied as often as they will release nutrients over a much longer period of time. Release times can be as long as 9 months depending upon the coating on the granules.

Water soluble fertilizers, as the name suggests, are fertilizers that will dissolve in solution. When mixed with water they can be sprayed on the foliage or used as soil drench. The nutrients are easily absorbed by the leaves or the roots. Some common water soluble fertilizers are Peter's 20-20-20 and Miracle Grow for Roses. Some formulations also have the micro ingredients. The water soluble fertilizers should be used as part of a complete fertilizer program. They are good for a quick pick me up. They may be more suitable for container grown plants.

Organic Fertilizers

The last type of fertilizer that you will be using in your all season fertilizer program is organic fertilizer. Organic materials are solely derived from once living matter. Organic fertilizers depend on soil organisms to break them down to produce nutrients for your plants. The living microscopic organisms need a warm and moist soil to become active; so this type of fertilizer should not be applied when the weather is cool.

Compared to synthetic fertilizers, organic materials contain very little nutrient value, but they do provide several important functions. They increase the organic and fungal activity in the soil; they improved the physical structure of the soil; and they make other nutrients more available to your plants when they decompose. To maintain the best soil structure, your rose beds need a constant source of organic material.

Some commonly used organic materials that rose growers use are as follows:

	Cottonseed Meal As a fertilizer is somewhat acidic in reaction. Generally, it contains about 7% nitrogen, 3% phosphorus, and 2% potassium. If you soil is a little alkaline, use this product to reduce you soil pH. There is little danger of burning.
	Blood Meal This organic material is dried blood collected from slaughter- houses. High in nitrogen and could burn you plants if used in excess of recommended amounts. Also contains some trace elements such as iron.
	Alfalfa Meal This organic material is ground up alfalfa which is generally grown as a forage crop. This material can be worked into the soil or used to make a tea. Don't apply too much because this material contains hormones that stimulate growth.
	Fish Meal or Emulsion This organic material can be purchased in dry and liquid forms. It is well rounded fertilizer that is high in nitrogen (about 7%), and contains several trace elements. This product can be used at times to promote a boost in plant growth. Be careful, too much can burn the leaves.
	Manure The material is a complete fertilizer, but it is more of soil conditioner because it has very little nutrient value. A fertilizer value of 1:1:1 is very common. If used, the fresher manures have a higher nutrient level; however cautions should be exercised in situation where the manure will contact fresh root growth, as it can burn. Harmful bacteria may be present in fresh manures, so they should be handled with care.
	Mulches The primary purpose of mulch is to preserve soil moisture and insulate the soil against wide temperature fluctuations. Regardless of what is used, it is organic material as it was once living matter. Although not normally used as a fertilizer, after decomposition it can be incorporated into the soil and it greatly improves the structure of the soil. As decomposition occurs, it may be necessary to add a little nitrogen, as that element is used in the decomposition process.

April

WHEN: After roses are pruned and when leaves start emerging.

WHAT TO APPLY:

1.    About 1/4 to1/3 cup of 12-12-12 granular chemical fertilizer per large plant and about one half of that for a small plant. Cultivate into soil and water in.

2.    Broadcast Urea (Nu Green) or Urea Formaldehyde (Blue Chip) on the beds for nitrogen replacement due to decomposition of organic matter. Blue chip is considered the best as it is a slow release type fertilizer. Be careful in using the Nu Green as it can burn. By broadcasting, I mean to sprinkle the fertilizer around the bed not apply it in quantities to each plant.

The ground is to cold for organics; only chemical fertilizers will work early in the season. Don't push your plants too much before the average last freeze date which is around the 25th of April in this area.

May

WHEN: About the middle of the month.

WHAT TO APPLY:

1.    Two cups of organic material can be applied when the ground is warm enough to start bacterial and microbial activity in the soil. The nutrients in the organic material will not be released until worked on by the soil organisms. Incorporate into the soil by spading fork and water in. The Indianapolis Rose Society makes an organic blend of Alfalfa Meal, Cottonseed Meal, Blood Meal, and Fish Meal. This mixture will be available in May for $10 per bag just in time for the first application.

2.    Apply a water soluble fertilizer as a quick pick me up at least two weeks before the spring bloom. Peter's 20-20-20 or similar well balanced fertilizer would be a good choice. Follow the directions on the container, but usually one gallon of liquid is enough for a large plant. Use one half of that amount for a smaller plant.

June

WHEN: After Spring Bloom is over.

WHAT TO APPLY:

1.    Apply another round of water soluble fertilizer like Peter's 20-20-20. Any well balance fertilizer will due. One gallon per large plant and one half of that for a small plant.

2.    Add one tablespoon of fish emulsion to the gallon of water.

3.    Add two tablespoons of Epsom salt (magnesium sulfate) to the gallon of water.

After the first of bloom, roses tend to put a lot of new growth. You want to make sure that there are plenty of nutrients in the soil to support the new growth. Although there are no empirical studies to support the use of Epsom salt, many knowledgeable rose growers believe that the magnesium sulfate will promote the emergence of new basal breaks which is something you want to encourage. The fish emulsion is a liquid organic material and it will be quickly available to the plant. Remember, anytime your plants are growing vigorously they need a lot of water.

July

WHEN: About the middle of the month.

WHAT TO APPLY:

1.    A water soluble fertilizer such as Peter's 20-20-20 at the rate of one gallon per plant; one half of that amount for small plants. You can use a balanced fertilizer with a lower nitrogen rating if you prefer as not as much nitrogen is required when the soil is warmer. Not too much is going on in the middle of the summer, except Japanese beetles, so don't push your roses too much. More importantly, make sure they get plenty of water. Never fertilize on a hot sunny day as you can burn the leaves and make sure the soil is well hydrated before you fertilize.

August                                              

WHEN: Organics in the first part of the month, and water soluble in the middle of the month.

WHAT TO APPLY:

1.    Apply another 2 cups of organic material to a large plant at the beginning of the month. Use a spading fork to work the material into the soil and water in well. After the organic material has been broken down, it will be available to plant for the fall bloom.

2.    Apply another round of water soluble fertilizer, such as Peter's 20-20-20 to give the plants a quick burst for the fall bloom. Apply one gallon per large plant and one half gallon for a small plant.

Do not apply any slow release fertilizers in late summer, as you do not want to encourage late fall growth. New growth put on late in the year will not have sufficient time to harden off before winter. Do not apply any type of fertilizer after August.

General Information

Don't forget that you can foliar feed you roses as you are applying fungicides and insecticides. I like to add a little Monty's Joy Juice to my fungicides when I'm spraying for black spot. Follow the instructions on the bottle before adding to any chemical formulation.

Remember that water is very important in successfully growing roses. The roots of your plant can not take up the nutrients unless they are in solution. In other words, if you let your rose beds dry up, the plants cannot take up any nutrients. If you are in a situation where you need to water and fertilize, and you only have time to do one thing; your choice should be to water.

Oxygen is also a very important element is plant growth. Keep the soil loose by using a spading fork to work the soil around the base of your plants. Do this at least twice during the summer.