Digging into rose fertilizers

Your roses are flowering plants, so they need food in order to grow and bloom successfully like most of them. But roses have greater nutritional needs than many plants. They only get small quantities from existing soil therefore extra fertilizing is essential if you want your roses to perform at their best.

Macronutrients

• N – P – K = Macronutrients for the whole plant
• Nitrogen (N) = greening, leafing, & visible plant health (UP)
• Phosphorus (P) = root health & nutrient absorption (DOWN)
• Potash (K) = think vitamins for all around plant health (ALL AROUND)

Up / Down / All around is really what you need to remember

So here’s some more on N – P – K

These are found in almost all plant & garden fertilizers, dry or liquid. Your local nursery will have a section under cover for just garden fertilizers, so you can look them over & ask questions of the staff before you buy.

The ratios of these 3 ingredients are different from bag to bag, for different emphasis, as the plant needs them during different parts of the season.

Nitrogen ( N ) promotes healthy vegetative, green growth. Since nitrogen is a component of all proteins and because water washes it away from the root zone, roses require a consistent supply. It is needed to build chlorophyll and allows the plant to use light to turn water and carbon dioxide into sugars to feed itself. Too much and you produce lush plants with few or no blooms. Too little, and the rose will have yellow leaves, no new growth, and small pale roses.

Phosphorus ( P )  makes for strong roots and abundant flower production. Too little will cause dull foliage, falling leaves, weak flower stems and buds that will not open.

Potash( K ) encourages vigorous growth and makes sure all is in good working order. It is like an immune system booster that helps the plant through stressed times such as disease / insect damage, drought and cold temperatures. Lack of the potassium in potash will produce weak stems, poorly developed buds, and yellow edges on the leaves, which turn brown.

A bloom-oriented formula, for example, will usually have a low or zero number for nitrogen (N), since blooming is driven by the roots and available nutrition. So it’ll say 0-20-20 perhaps.

Nitrogen is needed for advanced leaf creation to lead to greater photosynthesis during the whole year. A typical lawn fertilizer will emphasize the (N) in a 28-14-20 bag for lush greening as an example.

Micronutrients

Micronutrients like Calcium (Ca) increase the strength of cell walls; enables a plant to better ward off sucking insects like aphids.

Magnesium (Mg) found in magnesium sulfate is a crucial nutrient that promotes dark green leaves, intensified flower color, increased flower production, and can also help flush harmful salts through the soil.

That’s why Epsom Salt (a form of Magnesium Sulfate) is an economical, time-honored supplement for rose gardeners.

Apply at a rate of 1/3 to 1/2 cups per plant at the beginning of the growing season so the plant has time to take all that nutrition up over the following month of heavy growth.

Trace micronutrients

Trace Micronutrients are included in many of the macro-nutrient formulas in small percentages along with N-P-K. The plant doesn’t need high volumes of these, but a constant supply of trace amounts is important.

Alfalfa Meal is another staple of the rose grower.

Side dressing the plants at the stem and mixing alfalfa meal with the soil gives the plant a boost that acts like large doses of B-vitamins to our bodies.

It can’t hurt, & most competitive growers I know use it 2 times per growing season after their 1st bloom.

Ask the rose exhibitors and arrangers – they swear by it.

“All of it is really an investment in your garden soil. Managing good composted soil is as important as fertilizer“

Etienne

Is organic better than inorganic? How do you decide?

The choice is ultimately yours, but remember this: ALL of the above nutrients are necessary for roses to thrive. Look for a balanced, high quality rose fertilizer that includes macro-nutrients as well as micro-nutrients, and even trace micro-nutrients.

“Roses make no distinction between the type of fertilizer they receive, as long as the nutrients are available.“

Master Gardener Handbook 2005

Organic fertilizers include manures, compost, or other plant and animal products like alfalfa, bone meal, fish fertilizer, kelp extract, etc. Their nutrient content is usually low, to avoid burning roots – so use it on a continual basis.

Better for the environment, builds humus and improves soil texture, and feeds soil micro-organisms. Healthy soil makes for healthy roses.

Prices are normally higher for organics, but try making your own to save money (if you have access to organic materials such as aged manure, kitchen scraps, composted yard debris, or lawn clippings.) Compost feeds the soil.

For more criteria from the Master Gardeners, check here.

Fish Emulsion or Fish Fertilizer is highly recommended and provides an excellent nitrogen source. It is safe for all plants and will not burn the roots. Alaska Fish Fertilizer has an N-P-K rating of 5-1-1. ( Wear glove & old clothes . . . )

Alaska Fish Fertilizer Qt  5-1-1

Inorganic fertilizers = man made

They make up the bulk of what is offered at theyour big box store.

• They offer ease of convenience, and are usually more concentrated, and less expensive than organic products.
• They are available in a variety of forms, including water-soluble (liquid), granular, and slow-release. Most are fast release, though.
• They can burn roots if not applied properly.
• They do not help to condition the soil long-term, so they have no positive residual effect season after season.

Sources: Wikipedia, Home Depot, Alaska Fish,