The following are some tips which may be helpful when choosing fertilizer for feeding roses:
1) Use a high quality fertilizer (2-3% Nitrogen).
High quality nitrogen fertilizers have been tested and proven effective. They will not cause any problems with your roses. You need to choose a fertilizer that contains 2-3% nitrogen because it’s the amount of nitrogen that is most beneficial for your roses.
2) Choose a fertilizer that is labeled “for roses” or “rose food”.
These types of fertilizers contain less than 1% nitrogen. If you use a fertilizer that does not say “for roses”, then it might be too much for your roses.
3) Make sure the fertilizer is organic and free from chemicals.
Some garden centers sell fertilizers made with synthetic materials such as ammonium sulfate, potassium nitrate, sodium bicarbonate etc. These fertilizers are toxic to roses.
4) Avoid using fertilizer that says “for roses” or “rose food”.
Most of these products contain more than 3% nitrogen. This type of fertilizer is harmful to your roses.
5) Do not buy any product that states it is a “Rose Food” but doesn’t specify if it contains less than 1% nitrogen.
You must make sure that the fertilizer contains at least 2-3%.
6) If you have a brand of fertilizer that you are accustomed to using, and it doesn’t say anything about roses or if it doesn’t have the right percentage of nitrogen, don’t use it on your roses.
7) If you choose to use a fertilizer with less than 2-3% nitrogen, then you need to use more fertilizer.
You need to apply more than 1 pound of rose food per 100 square feet of garden soil. If you want to use a low nitrogen fertilizer on your roses, then you need to apply more of it.
8) Don’t just focus on the percentage of nitrogen in the fertilizer.
You need to read the entire label to determine if the product is safe to use on roses and if it is really a rose food.
9) If you have a brand of “rose food” that you like, and it doesn’t contain 2-3% nitrogen, then contact the company that makes it.
Ask them if their product is safe to use on roses and if it really is a rose food.
10) To be on the safe side, just use a fertilizer with 2-3% nitrogen. Using more than 1 lb of rose food per 100 square feet will not harm your roses.
Choose rose fertilizer that contains nitrogen, phosphorus, and potassium. These nutrients are commonly known as NPK. Nitrogen promotes green leafy growth.
Phosphorus promotes root growth and bloom development. Potassium encourages strong cell development, which is important for flower and fruit production. Most roses need 5.5-8.0 (numerical) or 5-8 (percentage) of nitrogen, 1% phosphate (phosphorus), and 0.5-1.5% potassium (potash). Some roses may need more or less of these nutrients. Do your own research if you need to.
Blood Meal: 2-3-1. Blood meal is good. It makes roses green up a bit, helps with lots of things, and has plenty of nitrogen.
Cottonseed Meal: 0.5-1-0. Cottonseed meal is okay.
It will give your roses a bit of nitrogen, but it’s not really enough unless you’re already giving it another source of nitrogen. Also, it can cause nutrient burn if the soil is extremely alkaline. It’s best if you spread it with grass clippings or oak leaves to lessen the impact on the soil.
Seabird Guano: 10-3-
1. Seabird Guano is excellent.
It promotes strong root development and has plenty of nitrogen.
Bone Meal: 3-12-0. Bone meal is great. It is slowly released and will give a long-term source of phosphorus, which promotes root growth and flowering.
High Nitrogen Covers Covered with Manure: Covered with either horse manure, rabbit manure, or any other animal manure (except cow) will provide a large amount of nitrogen. Use these as a top dressing for your roses. Be careful not to use too much otherwise it can promote disease and fungus.
Use 1-2 inches. Spread it around lightly as you water your roses.
Greensand: 0.5-0-0. Greensand is great for rose gardens because it is rich in various minerals and has a long-term source of potash, which promotes strong cell development.
Should I use anything else other than fertilizer for my roses?
You can use Epsom salt to help promote flowering if the soil has a magnesium deficiency. Apply 1-2 tsp. of magnesium-sulfate (epsom salt) around the base of each rose bush after their first bloom cycle in early spring.
You can use bone meal to help promote flowering if the soil has an phosphorus deficiency. Apply 1-2 tbsp. of bone meal around the base of each rose bush after their first bloom cycle in early spring.
You can use wood ash to provide potassium. Wood ash contains 0.2-1.0% potassium.
It also contains traces of phosphorus, nitrogen, and many other beneficial nutrients that are necessary for roses. Use 1-3 inches around the base of each bush.
I found something called ‘Rose Care’ at the garden center.
Is that good for my roses?
NO! More likely than not, it’s nothing more than a bag of fertilizer with some micronutrients added. Micronutrients are rarely added in excess to fertilizer (which is a good thing), so you need to add them separately anyways. If the package doesn’t specifically say that it has micronutrients added, assume it doesn’t. More expensive isn’t always better when it comes to rose fertilizers or any other kind for that matter. If it doesn’t list the micronutrient content, assume it’s low.
How do I know how much to apply?
First, you need to test your soil. Most places where people grow roses, the soil is extremely alkaline. You can check your soil by putting a blade of grass in some soil and then checking to see if it turns green after a few days (if it does, your soil is alkaline). You can also put a piece of aluminum foil in the soil, and then check to see if it slowly turns black (if it does, your soil is alkaline). If you have extremely acidic soil, you may need to add crushed oyster shell or another form of calcium carbonate to ensure that your plants aren’t deprived of calcium and other minerals.
If your soil is at the right pH level, you need to decide how much fertilizer you want to add. Roses are heavy feeders and will benefit from a lot of food, but too much can be fatal. You should start with a small dose (1 cup per yard) and work your way up from there.
You also need to consider when you plant your roses in relationship to when you’ll be fertilizing them. If you are going to plant your roses in the fall, you should add a 1/4 strength solution of fertilizer right away and then work your way up to a stronger dose. If you plant your roses in the spring, you can give them a 1/2 strength dose right away and then work your way up.
If you’re using the Epsom salt or bone meal method to promote flowering, follow the directions on the package for amounts (generally between 1 tbsp. and 1 cup per yard).
How do I apply the fertilizer?
Using a trowel or shovel, create a hole deep enough to reach soil that is not fertile (this will help control where your fertilizer is applied). Mix the fertilizer into the soil until it is thoroughly dissolved (you may need a few tablespoons of water). Then, follow the instructions above on testing your soil and adjusting your fertilizer levels.
How do I test my soil?
Get a small jar (like a baby food jar) and a piece of aluminum foil. Fill the jar with some of your soil and then seal it shut with the foil. Place it someplace where there is nothing to fertilize (lawn, non-flowering plants, etc.) for two weeks. Check on it periodically to see if the foil has turned black (indicating that chemical reactions are taking place, i.e. the soil is acidic). If it is, then your soil is acidic. If you want to be more precise, send a sample to your local Cooperative Extension Office and they will tell you the exact pH.
How do I adjust my soil’s pH?
If your soil is too acidic (below pH 5), add agricultural lime (available at farm supply stores) at a rate of 1 cup per 4 yards of soil. Work it into the top foot or so of soil and then retest.