Growing Fruit Trees in Pots
It is not essential to have a large garden to grow fruit trees. Miniature trees can be successfully grown in pots, and there is a long tradition of container and hothouse orchards. 18th– and 19th-century gardeners grew peaches, nectarines, oranges and other warmth-loving trees in containers in northern Europe. Growing fruit trees in pots is not difficult and does not require much work.
What makes it even better is that well-looked-after trees can produce normal size fruit and live in pots year after year.
Choosing a tree
When growing fruit trees in pots, it is important to buy dwarf patio varieties. Such trees are grafted on a dwarfing rootstock (such as M27) that will restrict the size of the mature tree. Patio apples, pears, cherries and plums are widely available. They are much less vigorous than other varieties, and therefore suitable for growing in containers.
Choosing a pot
You need a good quality frost-resistant pot, that will not fall apart damaging the tree. You can start with a smaller pot, about 10cm wider than the roots of the tree and, as the tree grows, replant it in a larger pot.
The final size should be around 45cm in diameter. The pot needs to have a hole at the bottom to allow free drainage. If waterlogged, trees will suffer and quickly die.
It is also a good idea to have a tray to put the pot in – it makes watering much easier.
Soil for growing fruit trees in pots
Soil-based compost, such as John Innes No. 3, is usually recommended.
Potting compost, sold in garden centres as a soil improver, is too light to be used on its own. It dries out fast and will quickly run out of nutrients.
Those who want to use their own mixture could try the following:
- 1/3 good garden soil (crumbly and rich in organic matter)
- 1/3 leaf mould from a wood or a park. Where deciduous tress grow densely, the ground is entirely covered with decomposed leaves that break down to form crumbly, rich soil.
- 1/3 fully decomposed manure (bought from a garden centre).
Old gardening manuals praise amazing fertility of soil formed by decomposed leaves on the wood floor. It is rich in organic matter and beneficial bacteria that make nutrients available to plants.
Planting fruit trees in pots
- Fill half of the pot with soil and firm the top lightly.
- Put in the tree – it should be planted to the same depth as it was grown previously. Bare-rooted trees will have a distinctive soil mark around the trunk showing the depth at which they were growing.
- If planting a container-grown tree, loosen and remove some of the soil at the base and around the sides of the root ball. Use a pot about 10cm wider than the root ball.
- If planting a bare-rooted tree, trim the fine roots by about 5cm. The main roots should be at a distance of about 5cm from the sides of the pot.
- Spread the roots around as much as possible, in a star-like pattern.
- Cover them with soil continuing to spread them, and lightly shaking the tree to ensure that spaces between the roots are filled with soil. It is very important not to leave any air pockets around the roots.
- Cover the top of the roots with 1-2cm of soil.
- Once the tree is planted, firm the soil around it lightly. Make sure to leave 3-4cm above the soil for watering.
- Water well, so that the entire contents of the pot are moist.
- If the tree is planted in spring, keep it in shade for a few days.
Watering fruit trees in pots
When growing fruit trees in pots, start watering early in spring. The soil in the garden may be still wet, but in the pot it will dry out much earlier.
In the summer water trees in pots frequently. In hot weather it is important to do this every day.
On a hot day a tree can be cooled and refreshed by filling the tray under the pot with water. The tray is generally useful, because it also prevents nutrients from being washed out of the soil – any water that runs into it is reabsorbed. If there is a long stretch of wet weather, however, particularly in winter, it is important to remove the tray, so that the tree does not sit in water.
It is also important to always make sure that the soil is moistened evenly throughout, and water does not just run off along the sides of the pot. If this happens, and the middle remains dry, the tree will drop its fruit and will eventually die.
To prevent this, regularly firm the soil around the sides of the pot and add more soil on top around the edges. This will ensure that the surface is somewhat higher around the edges. As a result, when the pot is watered, the water will gather at the centre.
Keeping soil in good condition
When growing fruit trees in pots it is important to feed them, because they have only a limited supply of nutrients available to them. During the growing period, in spring and summer, water with organic, shop-bought or home-made fertilizer every two weeks.
It is also important to replace the soil partially every year. In early spring, before the growth starts, remove about 7-8cm of soil from the top of the pot. Do it carefully with a blunt (wooden) instrument, so as not to damage the roots.
Trim off half the length of exposed fine roots and add new soil (the same mixture as at planting). The level of the soil should be the same as before.
Having done this, fill the pot to the top with well rotted manure. Water every day for 8-12 days. After this remove excess manure from the top to leave the normal 3-4cm for watering. This will improve the soil considerably and ensure that the tree has a good growing season.
Occasionally, about twice a month, loosen the soil on top to the depth of 1cm.
Exposure to sun
During spring and summer turn the pot frequently so that different sides of the tree are exposed to the sun. This will ensure more even and shapely growth.
Replant trees growing in pots every 2-3 years if they are developing normally. If, however, their growth has stopped, leaves are yellowing or there are any other signs of decline, replant them as soon as possible.
This is how to do it:
- Take the tree out of the pot in early spring before the growth starts. This needs to be done when the soil is dry.
- You will see that the roots have formed a dense net around the sides and at the bottom, and have grown out of the soil. Trim them with a sharp knife, cutting off 4-5cm on the sides and 7-10cm at the bottom.
- Water the root ball thoroughly before re-planting. If this is not done, the root ball will probably remain dry. This is because the water will run off around the sides of the pot, where spaces have been filled with looser new soil.
- Plant at the same depth in the same or larger pot in fresh soil.
- Keep in shade for 10 days. The tree will form new roots and will be rejuvenated.
Pruning fruit trees growing in pots
Trees have different pruning requirements. Apples and pears are pruned in late August or September. Remove any upright vigorous growth (it is likely to be minimal in dwarf varieties). Cut back all new shoots to 2-3 leaves.
Cherries, plums and peaches are pruned lightly in mid summer to maintain their shape and remove any crossing, weak or diseased branches.
Generally the growth of trees on dwarfing rootstock will be slow, but a tree will not be able to support a crown much wider than the width of its pot and much higher than the height of its pot.
Trees therefore need to be pruned to keep the width and height of their crowns in proportion to their root systems. If a larger crown is desirable, replant the tree in a larger pot.
Image credits: Ross Berteig