When to fertilize?

We are having days in the 60s and 70s now and my irises are about 4 to 6 inches high. However, we are subject to frost until May 5. Should I fertilize my irises now or wait until they bloom?

It is generally recommended to apply any necessary fertilizer 6 weeks before bloom.

Gee, that's about now! Thanks.

I never knew you are supposed to fertilize. What do you use? Now this could be the answer to some of my problems.
Kathy

Kathy, you shouldn't fertilize unless your soil needs it. Your county extension service or farm/feed store can send a soil sample from your garden to a lab for testing so that you'll know what, if anything, your soil requires in terms of fertilization.

Laurie

My soil is especially poor in phosphates so I use a lot of bone meal. But I will probably use a little nitrogen too. Maybe just Black Kow (composted manure).

I just discovered Black Kow. I used it to plant some iris in Mississippi. It has a nice texture, do you like it? It seems to have a little sand in it. That worried me.

Sand doesn't bother soil for irises. Anyone fertilizing remember to use low nitrogen type or plant will go to leaves.

Does anyone have suggestions for a particular brand or strength (example: 10-10-10 etc) ?
I don't fertilize much regularly--just some MG for blooms and a spritz of Messenger (not necessarily on the iris though) on a few things. When I go to look at the varieties I sort of stand around trying to figure out what to get (I look the same when buying over the counter cold medicines every winter).

I threw some 10-10-10 on mine this week. I usually plant them with Black Kow and bone meal.

We use 5-10-10.

Thanks...that helps a bunch:) I have some good compost so I can work a few handfuls in here and there.

Compost can work as well as commercial fertilizer.

Sand doesn't bother irises, but it sure isn't what I need in my already sandy soil! In fact, it isn't much good in clay soil, either.

I had heard that Black Kow had added sand, but I don't see it in my bags.

I thought I had Black Kow since I had purchased it before but I looked and it is actually Organic Valley Mushroom Compost. Didn't notice it being sandy or anything. I think I picked it up at HD or Lowes.

The arilbreds will like the sand. Sand mixed in with rich garden soil doesn't hurt. See you at convention if Am A decides to fly.

Oh, I hope Am A flies. They are supposed to be back in business on Sunday. I am flying Southwest on Tuesday. Hopefully it won't be absolutely jam packed, but it may well be. Be sure to put your DG name on your name tag. I will do the same.

dmac - I'd stay away from compost or manure now, in the spring. that sort of stuff should go UNDER them when planted, not beside them (top dress), on your beardeds. It's the beardless, I heard, that love that sidedressing.

Springtime I use either 0-10-10 or 5-10-10. key is low to no nitrogen on the beardeds, depending on your soil test.

If they are coming out and usually bloom in June for you, it's about the right time. I still haven't gotten to all my beds, and I'm still adding 0-10-10 as I weed.

(wrote dmac, meant to write woodspirit)

oh my. I threw some 10-10-10 on them. They look good. I sure hope they bloom well. Last year that late very cold freeze stopped all of them in their track and I didn't have a single bloom.

well, some folks swear at a touch of nitrogen in spring helps, others tell me it hurts - probably depends on your soil

I'm going to ask the experts, can you use milorganite on iris?
Becky

I looked up the chemical composition of Milorganite -- which I have used on my lawn. It is:

GUARANTEED ANALYSIS
Total Nitrogen (N) 5.0%
0.50% Water-Soluble Nitrogen
4.50% Water-Insoluble Nitrogen (Slowly Available)
Available Phosphate (P2O5) 2.0%
Calcium (Ca) 1.2%
Total Iron (Fe) 4.0%

The phosphorus content is pretty low for iris. The nitrogen isn't too high and is slow release, but I would use it with some bone meal or some other source of phosphorus. It is a good soil builder though and it is best to use it on things you don't eat, like iris, I have heard.

one iris grower sells iris fertilizer 6-24-24, so yes, low in that middle # for irises

I have heard skilled growers suggest fertilizing with 5-10-10 in the spring and some of them suggest bone meal only. I have also had a hybridizer tell me that she uses Bloom Booster which has a very high middle number when they first start blooming. I have also heard suggestions that rebloomers be fertilized again right after the first bloom. Just not much nitrogen is the most important part.

I just looked at my iris a few hours ago. some are putting up buds. But all of sudden I am seeing brown spots. What is that?

Have you had much rain? It could be leaf spot. If so you can trim the leaves below the spot.

I live by an iris farm and I purchase fertilizer from him.
www.comancheacresiris.com


I don't know how much it would cost to ship. It is good stuff.

No, not enough rain! We are getting some today however. I don't think it will amount to much more than an offand on drizzle.

I've been using fertilizer from Cooley's Gardens -- it comes in different strengths for spring fertilizing (which I put on 2 weeks ago) and for fall fertilization. My irises are looking fantastic.

I used Cooleys for years. Have too many irises now and cost is prohibitive. Love it, though.

for fewer than 50 clumps, I'd use Cooleys But get a soil test first.

bonjon, I looked at pictures on Google and they irises you sent me looked wonderful. But in my usual (at least for this year) scrambled brain way, I have lost track who gave me some others and they are wonderful too. Some of them went to my daughter's house as she has more land and specializes in Irises.
She amazes me that she likes to garden as she hated up when she was growing up. I guess that proves it never hurts to expose your kids to everything you can because you never know what might become their passion.