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low N fertilizer hurt plants/flowers that don't need it?

Posted by jardinerowa 10 (My Page) on
Tue, Jan 29, 13 at 15:47

Hey all!

My queston is about fertilization but it involves plants I started from seed so I'm posting it here.
My questions involves plants/flowers that supposedly do not need P and K fertilizers to bloom well. I've seen it said that plants like poppies, cosmos, gazania don't require fertilizing. I know it would be a mistake to give them a lot of N but what if I give them a little MORBLOOM? Could it hurt? The reason why I ask is that I started poppies months ago and I still see no signs of them wanting to bloom? Thanks!


Follow-Up Postings:

RE: low N fertilizer hurt plants/flowers that don't need it?

AFAIK the issue isn't so much that they don't need them - all plants need some - but that most garden soils contain more than enough phosphorus and potassium naturally, some contain excessive amounts. So the addition of high P and K supplements is simply a waste of money as well as contributing to the problems of run-off and ground water contamination.

However plants in containers rather than in ground are a totally different matter. Standard potting mixes do not contain ample P or K and any nutrients they do contain are frequently washed out as the container of so often watered. So supplemental feedings of a balanced fertilizer is necessary.

So which are we talking about - in ground plants or plants in containers?

If your plants are in ground and if your garden soil has tested out as low in P and K for some reason then supplements may be needed. However, there are a number of factors that contribute to blooming or not blooming. The only way you can know if the soil is the problem is to have it tested.

From the bit of research I have done on poppies - and no guarantee on its accuracy - I wouldn't expect most varieties to be blooming yet in your zone anyway. Most sources seem to indicate blooming time, depending on the weather, is 45-60 days after germination and late February to early March in zone 10. Sound about right?


RE: low N fertilizer hurt plants/flowers that don't need it?

Dave thanks for the well written response. I think you may be right about the poppies, maybe I just need to wait a bit more.

I should have clarified initially, yes I'm talking about plants in containers and I do know they get their nutrients washed out quite rapidly. I guess I can try low dose fertilizer (low N) and see what it does.

Thanks again!


RE: low N fertilizer hurt plants/flowers that don't need it?

Dave certainly gave good information, even guessing they may be in containers. Container mixes should be considered without nutrients unless specified. Most plants use nutrients in a ratio of 3-1-2, and if fed excessive amounts of phosphorus in an attempt to force blooming it is not used by the plant and is a waste. A soil test of my garden soil indicated both P and K at four times the recommended amount. When I questioned the lab, I was told such was not at all unusual for my area. For most plants to bloom well, especially poppies, the amount of sun they receive is more important than the amount of fertilizer. Al

RE: low N fertilizer hurt plants/flowers that don't need it?


Thanks for the information. I had no idea that soils generally have more than the needed P and K. To be sure, I have being very conservative with fertilizer and thinking that a little bit is better than a lot. Thanks!


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