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I know how fish emulsion works as a foliar spray on deciduous shrubs, but will it work on needle leaved evergreens such as mugho pines and junipers? If not, what should be used for comparable result?

J. Musser
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2 Answers2

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Foliar applications of fish emulsion, or pretty much any foliar nutrient application, is effective because the nutrients enter the plant directly through the stomata, or pores, of the leaves.

Evergreens have fewer stomata than deciduous trees but even needles contain stomata therefor foliar applications should also be effective. I couldn't find any specific research on fish emulsion and conifers but there are other studies showing foliar application of urea with positive results.

OrganicLawnDIY
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Yes it does. Just add a small amount to water and do a light mist over the leaves when it is not sunny. If it is sunny your spray will cause black spots on the leaves. The result would be leaves that are a little bit larger.

Most foliar fertilizers should be rich in micronutrients, Nitrogen(N) and Phosphorus(K). Here is a powerpoint that explains how foliar feeding works

user3084006
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  • There is nothing in the powerpoint reference that refers to evergreens. The plants they refer to are annuals and perennials. The question is about evergreens which have a thick waxy cuticle which is a factor that reduces the effectiveness of foliar sprays. Can you provide a reference for foliar sprays on evergreens? – kevinskio Dec 15 '13 at 15:49
  • Yes it does p 10, and p22. Citrus sinensis is considered an evergreen. – user3084006 Dec 15 '13 at 18:06
  • The question is about needle leaved evergreens. Citrus sinenesis is an evergreen that is hardy to zone 9 and considered frost tender. I cannot find anything that says that foliar sprays on needle leaved evergreens are very effective due to the waxy cuticle. – kevinskio Dec 15 '13 at 18:24
  • Agree with kevinsky - my answer to this question would be no, the spray will be ineffective. – Bamboo Dec 17 '13 at 13:52
  • @Bamboo Where is your evidence the spray is ineffective for conifers I found an article saying it is effective for absorbing nitrogen from the [University of Washington](http://www.cfr.washington.edu/research.smc/rfnrp/1FFC_Miller1.pdf) – user3084006 Dec 17 '13 at 23:38
  • @user3084006. Interesting article, and it proves they do take it up. I'll confess I'm not a lover of foliar feeds except on thin leaved plants growing in warm temperatures, when it is most effective. You can see from the article you refer to that burning is common in conifers which are foliar fed, so it still isn't something I'd recommend, unless you're growing Christmas trees by the acre, possibly, but even then the burn risk is an issue - no one wants an ugly tree. See puyallup.wsu.edu/~linda%chalker-scott/../foliar%20feeding.pdf re foliar feeding (she's Washington State Uni too) – Bamboo Dec 21 '13 at 12:48
  • @Bamboo I also mentioned that above. It depends on the amount of fertilizer you spray and the time of day. – user3084006 Dec 21 '13 at 19:45
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    I still think its not something amateurs should attempt, particularly on a few ornamental conifers. Certainly, repeated sprayings till run off on a frequent basis will be called for, and as you say, the timing and amount is critical. Easier and safer to improve the soil beneath. – Bamboo Dec 23 '13 at 17:59
  • @Bamboo that is with all foliar feeds if you over spray or do it at the wrong time you will get black spots – user3084006 Dec 24 '13 at 00:56
  • i suspect that it varies by species, in that the cuticle of a yew is probably more permeable than a single leaf pinyon... but without radio isotope testing, you would never be able to prove that it works – Grady Player Jun 11 '14 at 21:53