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When to Feed Apple Trees and When to Thin the Fruit

Question from Robin:
I put worm tea on my apple trees this month. I was going to add compost around them but don’t want to overdue the nitrogen.  What else should I add to their schedule? Nothing until early spring?

Also, thinned the apples to no more than 2 per spur. Is it best to thin them when they bud out and I can pluck off the weakest ones??

Answer from Pat:
Apple trees can be mulched at any time of year, but it makes most sense to renew the mulch after leaves have fallen and after you have pruned and raked the ground under the tree. Follow up with dormant spray and after that add a fresh layer of mulch. Don’t forget to do the dormant spray again a month or two later, though spraying twice is less important for apple trees than for peach and nectarine trees which are more prone to pests and diseases than are apple trees.

I know a gardener in an interior climate who mulches her apple trees, in fact everything in her garden, with horse manure in fall and lets the winter rains wash the goodness into the ground. If you did this to an apple tree in a coastal zone prior to cold weather I fear that the result would be it would leaf out before you want it to. Apple trees often do that anyway. In very mild coastal zones where it’s difficult anyway to get deciduous trees into dormancy,  it’s safer to stick to the schedule of fertilizing the tree lightly with an organic fertilizer at the time the flower buds swell in spring. If then you want to use manure as the fertilizer, that’s fine. As far as manuring in fall goes, you could try it one year if you wish and just see what happens. I really think trial and error is sometimes the best way to find processes that work in a particular garden even if they might not in another. Some gardeners get two crops a year off their ‘Anna’ apple trees. (This does not work for ‘Dorset’ nor even for ‘Ein Schemier’ that I know of.) It all depends on the garden, the soil, the climate, the fertilizer, and the gardening schedule of a particular gardener.

Regarding thinning the fruit, you should begin that process early in the season (as described in other entries on this blog regarding deciduous fruit trees) when fruit is about the size of an egg—much earlier than this (it is now October, close to harvest time, depending on the type of apple tree you have. But yes, for sure if some apples are small, weak, or diseased take them off now but it is probably too late to have any influence on the size of the rest of the fruit on the tree.

Comments

  1. Pat, my apple trees didn’t bloom this year. Is it too late to rectify? What can I do differently next year?

    Thank you

    • You do not say what climate zone you live in or what variety of apple you have. It is possible that vagueries of the weather failed to provide the tree with the temperatures it needed in order to bloom.When apple trees that usually bloom fail to bloom or when trees that never bloom are suddenly seen to bloom it is usually a result of day and night temperatures being different from what the plant needs in order to bloom or from vagueries in the weather. For example if you have a low-chill variety, a sudden frost at the wrong time of year might kill buds instead of stimulating their growth. Or a variety that needs winter chill in order to bloom might not have had adequate chill in order to bloom. Very often when apple trees don’t bloom it’s a result of trying to grow a ‘Delicious’ apple in the wrong zone. These are still sold to the unwary and some gardeners who don’t know better sometimes buy mail-order trees that are all wrong for their climate.

      The other possibility is that something else happened to damage the buds, such as a borer or other pest eating out the bud before they could open. These are other mechanical reasons, for example, flower buds might have been cut off by bad pruning. To give you an example with apple trees. Apple trees bloom on spur wood. If someone came along who was ignorant of this and cut off all the spurs in winter then you would get no bloom or so little that it would not be noticeable.

      There is one final reason that is often the case when a fruit tree does not bloom and that is when the tree has been pruned so heavily or when the tree was given so much nitrogen fertilizer that all it wanted to do was to grow and it put on a whole lot of green growth at the expense of flowers. Be careful not to over-fertilize deciduous fruit trees by giving them too much nitrogen since they will sometimes grow much green growth and many leaves instead of flowering.

      I have heard of trees failing to bloom when they were growing in heavy clay and rains rotted some roots. Root rot can cause a tree to drop off the flower buds.

      There is not much you can do now to stimulate flowering since flower buds should have already been made but if you have a low-chill variety such as Anna it might bloom later on in the year. You could try soaking the ground under the tree with a solution of 0-10-10 but I doubt it would help.

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