How should I care for a potted apple seedling?

Question

About two weeks ago, a friend of mine ate an apple and found that the seeds had already sprouted inside the apple. I thought this was pretty cool, so I put them in a cup to grow.

They grew into "real" seedlings, so when I went home for spring break, I potted them and brought them back, and since then, I've been growing them under my desk lamp (and inside a greenhouse I fashioned from a water bottle) over the last week. They have grown to about 3 or 4 inches and I was wondering how best to care for them from this point.

Should I find nutrients to give them? A special bulb? Is the greenhouse the best idea? When will I know when to transfer them to a bigger pot/split them up? Is there anything else I should consider?

Answer 1

Growing apples from seed does not usually meet people's expectations. They are not likely to be successfully grown indoors over several years and are very unlikely to bear any fruit.

• light requirements are high and it's difficult to match them without high pressure sodium or other high intensity lights.
• seedlings take longer to get to fruit bearing age (seven to ten years for apples) compared to grafted stock
• they are unlikely to be self fertile so you would need an apple tree of a different type to get fruit
• they are likely to grow much larger than the parent because most apple trees are grafted on a root stock that dwarfs their size for easier picking
• getting an edible and tasty apple is unlikely from a seed of random parentage
• all apple trees have a requirement for a variable amount of "chilling hours". Where I live this is 1200 to 1600 hours at 7 degrees Celsius. This varies by variety.

As an experiment this is a lot of fun but over several years is not likely to yield the result you expect.

Edit: @Throsby asks if seedlings from the same apple can fertilize each other. I have to give the answer I like the least: "It depends". You may get some fruit set but that assumes you have two mature trees (at maturity ~20 to 30 feet tall), that are growing outdoors in a region where you have cool temperatures on a seasonal basis in good light. It's hard to say....

Answer 2

In my humble opinion and experience.

Greenhouse for now is a good idea. For nutrients, I preferred to wait for the next pot. Prepare your soil first, so that the land and fertilizer will be well blended. Use a fertilizer for vegetables and fruit trees.

Now, think if you later want to continue to grow it in a pot, or you will transfer it in the garden. If your apple tree is likely to remain in a pot, do not fertilize too much to limit growth.

To decide the moment in which to transfer into a larger container, consider that the tree roots are the same size of the branches. When you see that the branches are too large to be contained in the vessel, that means that the roots have grown also. That is the moment for your tree to be transplanted.

About the bulb, we need to know how many hours of light, ho much sun and which temperature you have. At the moment, since spring has just started, and your tree has this light yet, I think you could let it for a while. But, before removing the lamp and possibly bringing the pot outside, I suggest you would focus on the thermometer!