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Nitrogen

michelle_co
9 years ago

Hi - I have been growing roses in my garden for several years now, and I still have problems getting good growth. I had soil analysis done this year, and the main nutrient missing from my red clay soil is nitrogen.

What is the best way to feed it to my roses? I have everything setup on drip, and I use a drip injector to feed a Miracle Grow type product a few times per season. I also put out about a cup of Milorganite, a cup of alfalfa pellets, a handful of balanced fertilizer and some compost around each rose during the season. So how do I safely increase the amount I am feeding without causing problems with salt buildup, etc.?

I have a bag of urea, and I also have chickens (hence chicken manure). I thought about using either of those amendments if possible. I don't compost because it's so dry here, I have never been able to get good results. I could put out some chicken manure in late fall, though?

Thanks!
Michelle

Comments (13)

  • hoovb zone 9 sunset 23
    9 years ago

    Nothing you could get would be better than your own aged chicken manure. If you are going to use MG, use the lawn fertilizer and then just use less of it.

  • michaelg
    9 years ago

    If you get a soil test in spring before fertilizing, it will almost always show that nitrogen is needed. That doesn't mean there was anything wrong with your program last year. Available N will have washed out of the topsoil, and bacteria in cold soil are unable to convert insoluble organic N into soluble, available N. They will start doing that when the soil warms.

    If you want a quick shot of N, you can scatter 1 TB of urea per plant and water 1/2 inch to dissolve it. Chicken manure also contains some urea, so don't overdo it. You don't need both within the same four weeks.

    Chicken manure is a good all-around fertilizer for roses, but it is high in sodium, which can contribute to salt problems, If you are in the mountains with good annual precipitation, that should not be a problem. Problems occur in dry climates where salty river water is used for irrigation.

  • michelle_co
    Original Author
    9 years ago

    Thanks @Hoovb. I was thinking I could try bag composting chicken manure this summer, and then apply it in Fall... There is also some goat and horse manure, but I'm kind of afraid of weed content. From the goats it would be more from hay/seeds mixing into their bedding.

    @Michael, unfortunately, I am in an arid mountain zone - 15" of rain annually if we are lucky. So the salt won't necessarily wash out well. Interesting about the soil test timing - yes, I did it in April and the soil wasn't very warm yet. My plants almost always suffer chlorosis in the Spring.

    The test also showed iron deficiency, would the Spring timing for the test affect that, too? If not, I picked up an iron/zinc liquid combo that I can inject with the drip system.

    Would it be worth doing a soil test later in the season, too?

  • mirendajean (Ireland)
    9 years ago

    Hiya. I strongly suggest you post your question in the soil/compost forum. They are true experts over there. I read their forum for educational purposes and have found their advice invaluable.

    M

  • michaelg
    9 years ago

    Yes, cold wet soil reduces the availability of iron to the plants. I don't know whether that shows up on a soil test. If after the soil warms, the young foliage is green, you don't need to worry about iron. Pale young leaves with green veins = iron deficiency in the plant.

    Nitrogen should not be a concern on the soil test, since you will add it every year. Pay attention to the other nutrients, the total salts, and the pH, as these tend to be stable for several years. If P or K test high, stop adding these for a few years. If magnesium is high, never add epsom salts, SulPoMag, or Dolomite lime. In a garden that has been fertilized heavily, harmful excesses are more likely than deficiencies--or excesses in the soil can cause deficiencies in the plant.

    The things that mainly cause salt problems are sodium, chlorides, and (present in western river water) bicarbonates. Poultry manure and blood meal contain sodium chloride. Manufactured fertilizer ingredients to avoid include potassium chloride (muriate of potash) and sodium nitrate (nitrate of soda),

  • hoovb zone 9 sunset 23
    9 years ago

    The manure needs at least a little air to compost properly. In anerobic conditions it's going to be quite disgusting. If you have the space just pile it and put one of those blue tarps over it for 6 months. Hold the tarps in place with a few rocks or bricks. Enough air gets in that way to keep the compost process going and the tarp holds moisture and odor in.

  • michelle_co
    Original Author
    9 years ago

    @Michael - The worst chlorotic rose in the garden is a rugosa. She really hates it here. :( I don't know what to do with her - either SP her or feed her something acidic? Crocus rose in my raised bed is also usually pretty chlorotic - I think she tries to take off too early in the season.

    My other garden numbers on the soil test - salt, etc. were all OK, and I have not heavily fertilized. It's an area that was an empty back lot that was never cultivated before. Our water is from a spring, so not bad for pH.

    I will check my bag of soluble fertilizer to see where it is with chlorides & Na Nitrate.

    @Hoov - I'll give it a try. I have room for a compost pile, if I can keep the tarp on and keep the rascally chickens from scattering it everywhere. :)

  • michaelg
    9 years ago

    Michelle--rugosas are notorious for going chartreuse in neutral or alkaline soil. Apply 1/2 cup of plain sulfur per square yard, under the mulch. Repeat in fall. By next spring the pH should have dropped some. Sulfur is slow acting but has a long-lasting effect. Micronized sulfur works fastest, but you can use whatever is in the store.

  • michelle_co
    Original Author
    9 years ago

    Michael, thanks again. I'll give sulfur a try and see if she decides to live. :)

  • kidhorn
    9 years ago

    One thing to be concerned about with regards to adding sulfur to lower the pH is if your soil has a lot of aluminum, the rose will tend to take up aluminum instead of iron. Hence exacerbating the iron deficiency problem.

  • michaelg
    9 years ago

    Kidhorn is correct that aluminum toxicity can be an issue in very acid soil, pH 4 or 4.5, so don't get impatient and keep reapplying sulfur,

  • michelle_co
    Original Author
    9 years ago

    Thanks - Are any other rose varieties that would appreciate a handful of sulfur annually?

  • michaelg
    9 years ago

    Any rose that grows out pale with green veins. But don't do it every year. It is a long-lasting treatment, and it takes a year to react on the soil.