Hey all,

I'm thinking about fertilizing my iris next spring. What fertilizer should I use to speed growth and blooms??? I thought about using Miracle-Gro® Water Soluble Bloom Booster® Plant Food. Would this be a good option???


Thank you,
~ Ian

P.S. I felt like I've created too many threads on this forum, and I apologize for creating so many. Sometimes Google doesn't have the right answers, and I rather leave my questions the professionals on this website.

Ian, no need to worry about starting new threads, if you have a question, it's perfectly fine to ask it! I'm sure there are a lot of different ways to go about fertilizing irises, but I think that it's a good idea to have your soil tested before you add anything. That's just my personal point of view. If you know what's in your soil, and what's not in your soil, you can add what it needs. That being said, if you have an iris bed that's been there for a long time, it's most likely going to need a boost now and then. For those beds I usually add a bit of a balanced fertilizer, that's one with all three numbers the same. I add it in the spring after the plants are coming out of their winter dormancy and the leaves are beginning to grow. The larger the number, the less you use. For example if it's 13-13-13, then you'd use less then if it's 10-10-10. Bloom booster is OK to use, but it's kind of high priced to treat a lot of irises. Some people like a 5-10-10, and that's fine, it's hard to come by that here, and often only available at a higher cost. I've never had an issue with using a balanced fertilizer causing too much Nitrogen and thus low bloom. I'm sure others have differing things that works for them, once again, each garden is unique and we all have to do different things depending on our soil conditions and climate. It takes some trial and error to find that sweet spot that works for your garden.

Hi Ian,
To make this simple, Iris do not flower well when fertilized with high nitrogen fertilizers. All fertilizers have three numbers on the packages, like 10-10-10, or 10-30-20 for example. Nitrogen is the first number. Choose a fertilizer with a lower first number than the second and third. Schreiner's Irises sells an Iris appropriate fertilizer on their site which is a 6-10-10 Controlled Release Iris Food. I hope this helps.

I know we have had this discussion, on here,but I use bone meal ,1 or 2 times a year depending on my motivation level.
Once 4-6 weeks before bloom.Once a month after bloom.I also try to use it when planting new iris.
I have used it for years with great success .It works for my soil type here.
Others have said it didn't work as well for them.Both fertilizer types mentioned are recommended for iris.
Animals do like to eat it if it is left on the top of your soil.

Bone meal works well, and I have used it. But you have to remember that it can take a very long time for it to break down into something the plants can use.

And even if you bury the bone meal, an animal can still smell it and dig!

I was using a spoonful of milorganite,at the bottom of the hole or plant pot, but just for the flowers,( considering how it's made.) Milwaukee sewage! ewww.
I had part of a bag left, so I'm using it up. I'm now on to bone meal.

I've also got some 10-10-10 I'm going to fling on the older beds. Home made compost when there's some left -after most of it goes on the vegetable beds!

I'll try bone meal.

I'm doing cicada bodies this summer. Just where they fell, all over the gardens. I figure that's enough for this summer. I'll be back to using 5-10-10 next March, and after the 2022 bloom.

What could be better than free fertilizer?