I read that spraying a fertilizer mixed with water is also used to help grow a tree faster/healthier.. What are your thoughts on this? I'd like to do an experiment with 5 young oak trees I've planted into full ground, spraying 2 or 3 trees once every week/every 2 weeks, and see the difference with the onces that don't get sprayed. Has anyone done this before? I would be spraying in the evenings with a liquid fertilizer (NPK 7-5-6) and water, not sure about the ratio yet though..

And would spray-fertilizing help to develop roots on cuttings or would a 0-0-10 NPK to the ground be better? Just curious if anyone has any experience with this. Thanks.

Foliar feeding is a way to do it, but I don't believe that it is good for all species. I don't thinkg it would help to develope roots on cuttings, fertilising when there are no roots IE cuttings is pointless as the cutting cannot absorb or produce food from the fertiliser. The roots take up the water and nutirents better the leaves, so I think it will not be of much benefit. You can foliar feed accassionaly, but not that often.
I seldom use foliar feed as a method of adding any fertiliser, usually I just spray water if needed over the leaves.

I just came across a text that said NOT to foliar feed (thanks for the terminology, English is not my first language) in mid/late summer since that would produce "soft, succulent growth" that is more susceptible to winter damage.. I might change my initial plan and only foliar feed a potted oak to see what it does compared to no feeding at all, since I can put them in a shed behind a window and prevent winter damage. Maybe get a set of three trees, one foliar fed, one soil fed, and one not fed at all..

Ok, well not adding any will restrict growth. If you winters are relatively mild, with not a not of frosts below about -8C then they trees will be fine. The only protection my trees get is from rain. If I can keep them drier, nto dry then they are fine. The big problem we get is when we have rain and then frost so that the pot freezes. Than is a problem. If the pots are protected from rain then they will be fine. The only exception is my Trident Maple. This goes under cover for the winter, but not frost free.

JohnnieWbl wrote:

I read that spraying a fertilizer mixed with water is also used to help grow a tree faster/healthier.. What are your thoughts on this? I'd like to do an experiment with 5 young oak trees I've planted into full ground, spraying 2 or 3 trees once every week/every 2 weeks, and see the difference with the onces that don't get sprayed. Has anyone done this before? I would be spraying in the evenings with a liquid fertilizer (NPK 7-5-6) and water,

While my intestines are capable of absorbing food, and certain pills are supposed to be inserted there, I prefer to eat my food through my mouth - I do not stick sandwiches up my... well, you get the idea. Likewise, I think it's better for a tree if fertilizer travels through the whole system, not just through the leaves.

Here's an article about the myths of foliar feeding :
puyallup.wsu.edu/~linda%20chalker-scott/...Foliar%20feeding.pdf

Foliar feeding can be benificial in certain cases, but the NPK amounts I think are irrelevant. See this article about deficiency of micronutrients in soil with a higher pH, making soil application of nutrients less efficient then foliar feeding:
journals.tubitak.gov.tr/agriculture/issu...r-37-4-5-1206-56.pdf

and another one concerning foliar feeding of Bonsai:
ofbonsai.org/the-last-page/editorials/de...-the-myths-of-bonsai

Thanks for the articles, I'll read a lot more probably after I encounter the big problems. Just read the last one but am not convinced by Linda's "debunking of the foliar feeding myth." She claims that the truth is that foliar feeding offers no advantages at all to the bonsaist but in this article she does not cinvince the reader with arguments. Her research is said to be a "surprise to bonsaist":

Tree and shrub species differ dramatically in their ability to absorb foliar fertilizers.
I really hope this doesn't surprise any bonsaists.. Again, I am new to this but my guess would be that that's indeed the case.

Micronutrients are the only minerals that can be effectively applied by foliar feeding and too much of these can damage or kill a plant.
I'd like to see a a definition of "effective" here. Sure, it might be more effective, that doesn't mean NPK solutions can also help.

Foliar spraying is only a temporary solution to the larger problem of soil nutrient availability.
Like any fertilizer is a temporary solution. Not meant to be a permanent adjustment to the tree, I think.

Any benefit from foliar spraying of landscape trees or shrubs is minor considering the cost and labor required.
Her initial claim is about bonsai trees, and she supports that by claiming it's not cost/labor effective for regular landscape trees? If I have 5 small trees I'd like to spray, it would take me 10 sprays, less than 1 minute.

I think the comparison between leaves and your anus is not really relevant here.. I believe it would be better to compare them to your pores, which are also capable of taking in some nutrients (vitamins through light, moisture through water, etc) while they also excrete stuff (sweat). Anyway, I'd like to experiment just for the sake of it.

I think the comparison between leaves and your anus is not really relevant here.. I believe it would be better to compare them to your pores, which are also capable of taking in some nutrients (vitamins through light, moisture through water, etc) while they also excrete stuff (sweat). Anyway, I'd like to experiment just for the sake of it.

Indeed that's a better comparison

I think the various articles do give information when folar feeding can be useful, and personally I think it is of limited use for bonsai that are fertilized properly. As mentioned on one of the pages I referred to, I think the effects that are noted actually are caused by the fertilizer dripping off the leaves on to the soil...

I have no proof, so I am very interested in the results of your experiments.

so.. how is the experiment?