eXtension

growing fruit and nut trees from seed. Over wintering small fruit trees.

Asked September 11, 2015, 10:59 AM EDT

I started a bunch of apple, pear, plum, peach, and cherry trees from seeds in the spring. They are all in 16 oz plastic disposable drinking cups and only a few are big enough to plant. Should I plant the ones that are big enough outside now or wait a few weeks? When should I take the smaller trees inside to overwinter? Before or after the leaves fall off? Where is the best place to overwinter them?

I overwinter potted strawberry plants in large rectangular flower pots. I have an unheated room in my basement where I overwintered the strawberries one year but the young runner strawberry plants don't make it through the winter in there; only the older plants survive. I also have an 100-year-old milk house where I usually overwinter the strawberries and most survive, but I am concerned it might be too damp in there for the fruit trees. I never have to water the strawberries in there because the soil stays damp in the winter. Sometimes there is condensation in the milk house in the winter too.

Which would be the best place to overwinter the fruit trees? Since they are in clear plastic drinking cups I can see a bunch of the trees have roots that are growing down the sides of the cups or growing around the bottom. Should I put them in bigger cups to get more soil around the roots? If so should I do it before or after the leaves fall off?

I also have 6 mulberry trees that I started this summer. They are in small plastic flower pots on my windowsills. Should I overwinter these with the other small trees, or would they be fine in the house over the winter on the windowsills?

I have also collected hickory nuts and butternuts. Should I refrigerate these nuts now for stratification and then put them in peat moss or paper towels in January or February? I have tried looking up information on how to plant these but I keep finding conflicting information.

Westmoreland County Pennsylvania

1 Response

Almost every horticulturist will have a slightly different view on your questions, but here are my thoughts:

1) I would prepare an area in the garden bathed in full sunlight away from black walnut trees. I would transplant every specimen irrespective of its size in the garden and overwinter them there in that location. No outdoor species should be overwintered inside a home or outbuilding. Nurseries typically overwinter very small seedling stock outdoors in beds and coldframes. A light layer of straw may be used to mulch around the plants to provide some degree of winter protection. I would erect a a wire mesh barrier or fence around the entire planting to keep rodents and rabbits out. Rodent damage is your greatest risk in outdoor plantings. Since the plants were started in cups, there is a great risk of girdling roots forming. Please make sure that you disturb the circular root pattern prior to transplanting into the garden. You may accomplish this by using a heavy serrated knife to cut the rootball. The mulberries should be overwintered in a similar fashion. If you decide not to overwinter them in the manner that was suggested consider using a structureless system using microfoam and two layers of white plastic. Please see this link: http://hortsci.ashspublications.org/content/25/9/1104.4
2) Regarding the nut species....you can use stratification techniques which means you artificially provide them with a cold period to encourage germination. Personally, I prefer doing this naturally. I till a section of the garden in full sunlight. I take a piece of sandpaper or a file and lightly abrade the hard seed coat. I plant each of the nuts in this prepared area and then lay chicken wire over the entire bed area. This prevents rodents from digging from above to steal the nuts. A light layer of straw should be spread over the chicken wire as a protective mulch. In early April, remove the chicken wire and the straw mulch. The hickory and butternut trees should begin to germinate in Mid-April using this technique. The scarification process coupled with the natural stratification technique should expedite germination.

3) Strawberry plants should be overwintered outdoors. Indoor areas are too warm, too dry, and too poorly lit to successfully overwinter most temperate species. Strawberries should have been planted in August and typically need to be mulched lightly with straw around Thanksgiving.