Thursday, October 6, 2011

to feed or not to feed, that is the question...

I was having lunch today with a friend and colleague, and she recounted to me the story of a neighbor who was fertilizing her shrubs this week.  Nothing earth shattering right?  Except both of us learned in horticulture school that one should not fertilize a plant when it's about to go dormant.  When she inquired as to why her neighbor was fertilizing now, she replied "because that's what it says on the bag."

We were both perplexed, especially because we are always advising friends, clients, etc to follow the instructions on the bag (since many people tend to think more is better - not often the case with fertilizer, organic or synthetic).  I came home and did a little research on the product in question, you'll probably recognize it...

Well known, organic and widely available, Holly-tone made by the Espoma company is a great product. In reading the fact sheet for this product it does indeed recommend a late fall feeding.  That might be great if you still have a long growing season to go, but here in the northeast (we had frost last night people) not so much.  Do you really want to encourage more growth exactly when the plant is in shut down mode? So if you are in zone 7 or lower (don't know your zone, check here) you may as well hold off until the spring, because you will either do more harm than good, or just be wasting product.


  1. Fertilizing woody plants in late summer (Aug.) creates too much tender summer growth that won't harden off and can get nipped later by frost. But fertilizing with a slow release low-nitrogen fertilizer (nitrogen "N" equal to the "P" and "K" elements) applied around frost time will do a lot of good for the roots, when the plant is going dormant. The plant won't have a growth spurt in fall, since it is programmed to go dormant, but the roots will continue to grow.

    Here's a great resource:

    This site says to wait until a killing frost and then apply fertilizer, but here in CT any time in October is good for woody trees and shrubs. It really does help the roots without creating any summer-type growth spurt this late in the season.

  2. Laurrie,
    You bring up some interesting points. I can only tell you that this is the way I learned it at school in New York, and the fact sheet that you shared, while having tons of great information is for North Carolina, and the same rules for root growth may not apply. Especially for shallow rooted plants like rhododendrons, which probably have the majority of their root system frozen all winter, not pushing out new growth. The other confusing issue is all the crazy weather we've been having lately, who's to say when a plant is actually going dormant? I'm curious now though, I'm going to check what cornell, uconn, etc. say about this. If it were just me remembering learning this in school, I'd easily say that my memory is fuzzy. But my friend remembered it as well, and while we went to the same school, she was a year behind me... I'll keep you posted!

  3. I've been reading the comments and thinking in layman's terms. What if you are trying to fall asleep and you drink some coffee? The caffeine will keep you awake (well, most of us). You never settle down and subsequently do not have a good night sleep. Conversly, if you are groggy in the morning and someone gives you some coffee, it will give you a jump start to your day.

    I'm thinking of fertilizer in the same way. Why would you give a plant, that is trying to go dormant, a message to "grow"? I would somewhat agree that it would be ok after a hard freeze or very late winter/very early spring to send a message "it's time to wake up and grow". But fertilizing now is just a waste of time and money. Just fertilize in the early spring.... Timing aside, really and truly, your shrubs shouldn't need more than 1 feeding/season anyway...

  4. Or if you're like me, you don't fertilize your shrubs at all - a few forkfuls of compost is the best they're likely to get around here. My tough love approach to plants has never failed me...