Roses: They are beautiful...

Rosa 'Abraham Darby'  

Roses are beautiful when they are not ugly.  All cultivated roses were selected or bred for appearance and/or in combination with fragrance, disease resistance, vigor and many other desirable characteristics.  They are all beautiful to begin with.  However, we all know that sometimes the promised beauty does not surface due to a number of factors. With more than two decades worth of experience in growing roses in California, I've come to realize a simple truth - there exists no spectrum when it comes to the outcome of the rose. There are only two opposing classifications: beautiful or ugly.

A rose plant growing under optimum conditions and cared for by a conscientious gardener, will come out to be a poetic symbol of beauty, love, fragrance and art.  A rose is a rose when the world is fair. But the world is not always fair.  There are microorganisms lurking everywhere - in the air, in the soil and water - just waiting for the its carrier and opportune moment to charge the garden.    The weather that dictates production rates of plants can be austere or excessive with its blessings and sometimes favors the proliferation of the microscopic society with its ever changing combination of humidity and temperature. All of these natural factors contribute to the outcome of roses.  Then there is the gardeners and his/her management techniques or lack thereof.

Rosa 'Evelyn'

They are beautiful this year.  Their leaves are clean with no significant diseases to worry about at present - hopefully it will stay that way. With the exception of the ones that are shaded by trees, all are growing better than in the previous two years.  The sweet fragrance emanating from the David Austin rose 'Evelyn' is very pleasant that even after many years of purging my rose collection, I thought of checking the rose catalogs again.  :)

Rosa 'America'

Although, the natural factors remain to be out of my control, there were some things that this gardener did that possibly contributed to the excellent performance of the roses during the current season.

1. Deliberate choice and timing of fertilization.  Complete fertilizer (16-16-16) was applied to all my roses right when the new buds were about three inches long and around the time when we had some rain in February.  This is key to the vigor of the roses in the early spring.  A second application was done during the first deadheading.

2.  Limited but regimented watering due to statewide water conservation. Watering is regulated in our area - this time we can only turn on our irrigation systems twice a week.  This means that we are not in danger of over watering the plants and daily exposure to moisture on the leaves.

3.  Increased presence of birds in the garden.  The birds like to linger in the yard with the consistent provision of food and water.  As a result they are also there to peck on bugs before they become a problem.

4.  Improved soil condition through generous application of mulch.  Our pet bunny uses sawdust pellets as bedding material which in turn becomes mulch for the flowers and shrubs.  We all know the benefits of mulch in soil moisture conservation, weed control and soil structure.  And yet, here we have a bunny-enhanced mulch with higher nitrogen content!  Beyond all these perks, the decomposition process of the sawdust reduces the soil pH to some extent.  Since roses prefer a slightly acidic soil, this practice has positive effects on roses.

Rosa 'Sally  Holmes'

Roses are beautiful when they are not ugly.  :)

What's in the Label?

What Do Fertilizer Labels Mean?

Commercial fertilizers, by standard, contain at least one of the three primary nutrients (N), phosphorous (P), and potassium (K).  Phosphorous and potassium in their elemental form cannot be absorbed by the plants.  In fertilizers they come in a form that is useable by plants.  Phosphorous comes in the form of phosphate (P2O5) while potassium comes as potash (K2O).  Fertilizer qualifies to be a commercial grade only when it contains more than five percent of N, P2O5 or K2O.

Every bag of commercial fertilizer is labeled with three numbers separated by dashes as shown in the above picture.  These numbers reflect the percentage of the three primary nutrients in the fertilizer, the first number being nitrogen (N) - the second number is phosphate (P2O5) - the third number is % potash (K2O).  The label always lists the nutrients in this order.

16-20-0 is a fertilizer containing 16% nitrogen, 20% phosphate, and 0% potash.  Mixed fertilizers (fertilizers that contain two or more of the primary nutrients) either complete or incomplete, are made by combining different single-element sources to form a desired blend.  Because of this combination, the resulting fertilizer mix may have particles of varying colors.   In as much as plants require different proportions of the primary nutrients, manufacturers produce different grades. 

How to determine the nutrient content of fertilizers

1.  Fertilizer grade (example 6-10-10)

2.  Total weight per bag (example 50 lbs)

3.  To determine the nitrogen (N) content:  50 lbs x 6%

                     50 x .06 = 3 lbs N

4.  To determine the phosphate (P2O5) content:  50 lbs x 10% P2O5/lb fertilizer

                      50 x .10 = 5 lbs phosphate

5.  To determine the potash content:  50 lbs x 10% K2O/lb fertilizer
                     50 x .10 = 5 lbs potash 

6.  The total amount of nutrients in the 50-lb bag of fertilizer is 13 lbs.  The rest is inert filler material.

7.  To convert phosphate into phosphorous and potash into potassium the following conversion rate are necessary:  1 lb of P2O5 = 0.44 lbs P; 1 lb of K2O = 0.83 lbs K.  So, we already know that there are 5 lbs of phosphate and 5 lbs of potash in a 50 lb bag of 6-10-10. 
To convert phosphate in to P:  multiply phosphate weight by 0.44 lbs.
        5 x 0.44 = 2.2 lbs P
To convert 5 lbs potash into K:  multiply potash weight (lb) by 0.83 lb/lb K2O
        5 x 0.83 = 4.15 lbs K

It is important to master this simple math skill because it is a tool in determining the economics of your choice of fertilizer.

Functions of the Three Major Elements

To appreciate and understand the meaning of the fertilizer grades, one must understand the functions of the elements that are featured in the fertilizer labels. 

Nitrogen (N) is the major element that affects vegetative growth of plants.  Sufficient nitrogen results in good foliage which key to producing a good crop.  Nitrogen is a major component of plant proteins, chlorophyll, vitamins, and enzymes.  It is gives the green coloring of the plant.

When nitrogen is deficient, plants exhibit stunted growth, chlorosis or yellowing on older leaves, premature death and poor yields.

Nitrogen is a plant-mobile element, therefore the symptoms of deficiency are observed on the older leaves. 

Phosphorous (P) promotes early root formation and growth.  It is a component of some enzymes and proteins, ATP, RNA and DNA necessary for plant development.  Phosphorous also promotes healthy development of the reproductive system of the plant.  When we say reproductive system we are referring to the flowering, fruit setting and seed development.  

Deficiency on phosphorous is manifested by stunted growth of plants, unusual dark green and purple pigmentation on leaves, poor fruit and seed development, and delayed maturity. 

Unlike nitrogen, phosphorous is an immobile element hence, the deficiency symptoms are usually noticed on the younger plant parts.

Potassium (K) is necessary in the following plant processes:  formations of sugars and carbohydrates; protein synthesis; and cell division.  It is enhances flavor and color on flowers, fruits, and vegetable crops.  It also helps increase fruit size and quality which results in better marketability of produce.  Potassium helps build resistance of plants to diseases. 

Plants that are deficient to potassium exhibit the following symptoms:  slow growth resulting in low yields; scorched or burned appearance on leaves; necrosis on mature leaves; weak stalks resulting in lodging; and small fruits and shriveled (undeveloped) seeds.

Therefore  a fertilizer that has the label 6-10-10 (6% N - 10% P  -10% K) is intended to promote a healthy plant growth giving special emphasis on root and fruit development just like what a gardener would on his tomatoes.  On the other hand, a fertilizer with a label of 21-0-0 (21% N and 0% P and K) is intended to meet the needs of a plant to develop healthy foliage.  It is usually applied on lawns and non flowering and fruiting shrubs.  The fertilizer 16-20-0 is a formula that's used to provide nitrogen and phosphorous needs of plants.  The emphasis here is foliage growth and root and flower formation.  This also can be used in areas where K is needed but the soil has sufficient amount of K2O.

Pointers to Consider Before Choosing your Fertilizer:

1.  Have your soil analyzed. 
Soil analysis result will give you a customized fertilizer recommendation for your garden.  Collect soil samples.  Assign five locations that represent the different sections of your garden.  Collect soil by cutting straight into the soil up to about one foot deep.  Avoid scraping only from the top soil.  Air-dry soil samples.  Mix a you pulverize the samples.  Put them in a bag and send them to a soil analysis lab in your area.

2.  Observe your plants
Observe how your plants grow.  Look for unusual appearance and behavior. (I will remind myself to post a list of the most common deficiency symptoms as reference.) 

3.  Acquaint yourself with general knowledge
The soil in general contains all the essential elements for plant growth.  Some elements are more abundant than some.  Nitrogen, because it is absorbed by plants in large quantities, and can be lost easily through leaching and immobilization, needs to be replaced more regularly than P and K.  Phosphorous is often bound in the soil due to soil unfavorable soil pH (soil acidity).  Water plays an important role in making the elements available for plant uptake. 

4.  Avoid fertilizer overdose
Fertilizers are like medicines.  They are helpful in the right amounts but can be toxic beyond a certain level.  Addition of any element to the soil will result in a change in the soil chemistry.  Sometimes, too much of one thing will bind other element making them unavailable for the plants thereby solving one problem by creating another.  Always follow the recommended rate and procedure of application.

5.  Pricey does not always mean better
Now that you know the meaning of the labels, you should be able to determine which bag gives you the nutrient at the least cost per unit weight.

Organic & Inorganic Fertilizer

Fertilizer is any soil amendment that is guaranteed to contain a minimum percentage of nitrogen, phosphate or potash.  There are two types of fertilizers according to their source: organic and inorganic fertilizer. 

1.  Organic fertilizers or Manures are soil amendments derived from fully decomposed plant remains and animal excrements and by-products or a combination of both that is guaranteed to contain one or more of the essential nutrients other than carbon (C), hydrogen (H) and oxygen (O).  Organic fertilizers generally have low nutrient content, thus significantly large volume is required for application.  Based on the cost of nutrient per pound, manure or organic fertilizer is generally expensive.  However, organic fertilizers or manures contain a variety of essential micro-nutrients that plant need.   They also help improve the physical and chemical properties of the soil by increasing soil organic matter content.  Compost, animal manures, green manures, bone meals, fish meals, and blood meals are common examples of organic fertilizers.

Even human manure is also a source of organic fertilizer.  Although human feces and urine as fertilizer, modernly referred to as Humanure, is just beginning to shine in this part of the globe, it has been used in China, where it is called Night Soil, for thousands of years.  I have seen toilets built along the rural roads of southern China where the tank is left open for easier collection.  

Green Manuring is the process by which a crop, usually a ground cover,  is planted and then plowed under and allowed to decompose in order to add nutrient and organic matter in the soil.  Green manure crops are grown to improve the soil and indirectly improve crop yields.  Plants used as green manure are generally fast-growing, herbaceous, and fast-decomposing.  I'd prefer "green-manured" salad than its "humanured" counterpart...psychology seems to mess up my scientific view of the matter.

The nutrients from organic materials have to be broken down into inorganic molecules before they can be absorbed by the plant.  This process by which organic material is converted into forms useable by plants is called decomposition.  Decomposed organic material is called compost.  Soil bacteria action hastens decomposition and bacterial activity is a function of temperature.

2.  Inorganic Fertilizers or Synthetic Fertilizers are manufactured from natural materials such as petroleum and natural gas.  They contain high percentages of nutrient content.  When applied properly at the right amount, they result in relatively fast plant response.  On the other hand, it is also easy to apply too much fertilizer, causing damage to the plants.  Nutrient from inorganic fertilizers is released readily in the soil varying slightly depending on the fertilizer.  Since the nutrients are readily available, there is a higher risk of nutrient loss through run off or leaching. 

Nitrogen, phosphorous and potassium commonly known as NPK are the elements required by plants in huge quantities.  Because of this they are considered the primary elements.  When there is a deficiency of these elements in the soil, the plants show symptoms of abnormal growth and development.   Inorganic fertilizers are classified based on their NPK components: complete and incomplete fertilizer.

• Complete Fertilizer is any inorganic fertilizer containing nitrogen, phosphorous and potassium.  NPK are required components of complete fertilizer.  Complete fertilizer comes in different fertilizer ratio which is the relative amount of N to P to K.  In other words it is the proportion by which the elements are represented in the fertilizer. The fertilizer ratio can be calculated by dividing the greater grades by the least grade.  A triple sixteen (16-16-16) has 1:1:1 ratio, while 30-10-20 has 3:1:2 ratio.   By varying ratio farmers or gardeners get to choose the right fertilizer depending on the requirements of the plants and the condition of the soil they work with.  Fertilizers with the same ratio do not have to have the same grade.
• Examples of complete fertilizers:
• Triple twelve  (12-12-12)
• Triple sixteen (16-16-16)
• Thirty ten twenty (30-10 20
• Incomplete Fertilizer is a synthetic fertilizer containing one or two of the primary elements (N), nitrogen, phosphorous (P) and potassium (K).  They can either contain just one element or a combination of any two of N, P, and K. These are useful for application in areas where only one or two of these three elements are deficient.  Incomplete fertilizers may be combined to form a complete fertilizer when necessary.
• Examples of incomplete fertilizers:
•  Ammonium Sulfate (21-0-0)
• Ammonium Nitrate (34-0-0)
• Sodium Nitrate (16-0-0)
• Urea (45% N)
• Urea formaldehyde (38% N)
• Rock Phosphate (16% N)
• Super Phosphate (20% P)
• Triple Phosphate (46% P)
• Muriate of Potash (60% K)

Know your plants and soil, choose fertilizer correctly.

What are Fertilizers

Myth:  Fertilizers are plant food.

Truth: Plants produce their own food.

Plants are autothrops, which means they are self -feeding.   They produce their own food.  While humans and animals consume other living organisms to survive, plants photosynthesize.  Plants contain chlorophyll that allows them to capture solar energy needed to convert carbon dioxide and water into sugars, carbohydrates and proteins that are necessary food for all organisms.

If fertilizers are not plant food then what are they?

Fertilizers are materials that contain one or more of the essential elements used as soil amendment.   Fertilizers can be applied to the soil or by foliar application, i.e. spraying to the leaves.   The essential elements become integral components of the food manufactured through photosynthesis.  Without one or more of the essential elements, the plants will not be able to complete their growth cycle.  That is the reason that they are called "essential" elements. 

Plant nutrition - refers to the plant’s need for and use of the essential elements for growth and development.  The essential elements are also referred to as nutrient elements.

Availability of these elements in the soil depends on soil fertility, which is the inherent capacity of the soil to supply nutrients to plants in adequate amounts and suitable proportions.  The soil naturally contains all these elements but the condition of the soil determines whether such elements are in available or bound in form.  To give you very simple example, nitrogen can be present in the soil but when soil moisture is limiting, nitrogen cannot be absorbed by plants.  Then there is soil chemistry that determines how these elements are attached to each other. Soil acidity, better known as soil pH, plays an important role is the availability of a number of the micro nutrients in the soil.  When the availability of these elements is limited in the soil, fertilization becomes necessary.  Fertilization is the application of nutrient elements to the environment around a plant to meet its nutritional need.

Beneficial Elements

Beneficial Elements are elements that help optimize the growth and development of plants but they are not essential for growth.  When they are absent in the soil, plants can still live a normal life.  Here are some criteria that separate beneficial element from the essential ones:

1. It can compensate for the toxic effects of other elements.

2.  May replace mineral nutrient in some other less specific function such as the maintenance of osmotic pressure.

3.  May be essential to some but not to all plants.

Examples of beneficial elements are:

Silicon (Si)

Silicon increases the resistance of plants to pathogen and pests.  It also increases drought and heavy metal tolerance of plants.  Overall it improves the quality and yield of agricultural plants. 

Cobalt (Co)
Cobalt is essential for the growth of Rhizobium bacteria for N fixation and thus beneficial for the plant.  Nitrogen fixation is the process by which the atmospheric molecular nitrogen (N2) is reduced to form ammonia (NH3).  This process is carried out by nitrogen-fixing bacteria which are found in the roots of most leguminous plants.  Ammonia is the form of nitrogen that is used by plants and other living systems in the synthesis of organic compounds. 

Lithium (Li)
Affects transport of sugars from leaves to roots.  Production of food (carbohydrates and sugars) happens in the leaves during photosynthesis.  This food will be transported to the different parts of the plant such as the roots, fruits, new shoots, and stems.  Lithium enhances the transport of such food to the roots.  

For the backyard gardener, there is no need to worry about artificially applying them to the soil or any growing media that you might use.  Your plants will still survive.  In case you want to insist, then the best thing for you to do is apply compost around your plants. 

Beneficial elements are not essential for plant growth.  Lithium for example, is indirectly beneficial to the plant by its benefits to the bacteria rhizobium.  Plants don't need the bacteria for growth.  They need nitrogen.  

Essential Elements

There are seventeen elements known to be necessary for plants to complete their life cycle.  They are called essential elements.

What Makes An Element Essential?
Arnon and Stout (1939) proposed the following criteria:
1. A plant must be unable to complete its life cycle in the absence of the mineral element.
2. The function of the element must not be replaceable by another mineral element.
3. The element must be directly involved in plant metabolism.

Of the seventeen essential elements, hydrogen (H), oxygen (O), and carbon (C) come from the air and water and by nature, readily available.  Although nitrogen can also be found in the air, its gaseous form is not useable by plants.  Along with nitrogen, the rest of the elements are found in the soil.  Depending on the soil properties, however, some of these elements may be present but not in forms that are useable for plant use.   Still some soils may lack one or more of these elements. 

When one or more of the essential elements is deficient, plants cannot complete their life cycle.  Such deficiency will be expressed in abnormal behavior in plant growth.  For this reason, fertilizers are used to supply the elements that are deficient within the growing area. 

Macronutrients 
Macronutrients are essential elements that are required by the plants in huge quantities (parts/100 of dry plant matter).  Macro nutrients are not in any way more important than the rest of the 17 essential elements. 
1. Nitrogen (N)
2. Phosphorous (P)
3. Potassium (K)
4. Calcium (Ca)
5. Magnesium (Mg)
6. Sulfur (S)

Micronutrients
Micronutrients also known as trace elements are elements that are required by plants in small quantities (ppm of dry plant matter).  Micronutrients should not be mistaken as less important than their macro counterparts. 
1. Boron (B)
2. Chlorine (Cl)
3. Copper (Cu)
4. Iron (Fe)
5. Manganese (Mn)
6. Molybdenum (Mo)
7. Nickel (Ni)
8. Zinc (Zn)

Scientists continue to evaluate the essentiality of more elements that are not included in the list.  Nickel for example, recently won the status of an essential trace or micro element.