Welcome to Top of the Crops - today, you will learn how to grow blank in a polytunnel. For more gardening insights, be sure to check out our blog Polytunnel Gardening too!
Peaches can potentially be grown outside in some parts of the UK, but a polytunnel makes it much easier to grow peach trees successfully in our climate, and makes this an option even for more northerly gardeners and growers.
A polytunnel can give the necessary protection from frost for the blossoms and then fruits early in the year. It can also provide a degree of protection from birds and mammals who also enjoy eating these juicy fruits.
In the UK, it is easiest to grow peaches in containers, so these can be moved to a warmer location when required. Alternatively, you may choose to grow peaches directly in the soil in your polytunnel.
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If you are interested in growing peaches then you will need:
Peach tree.
Suitable growing location.
(Container and growing medium if the tree will be container grown.)
Spade for planting.
Facility to water your tree (especially if growing undercover).
Small brush for hand-pollination.
Organic matter for use as mulch.
Tools for pruning (and support/ ties if training to a specific shape).
When choosing a suitable growing location for a peach tree, it is important to bear in mind their basic growing needs.
To grow successfully, peach trees require a location in full sun, and as much warmth as possible. They need a sheltered spot, out of cold winds, ideally with a stone or brick wall or other thermal mass to their north that will warm in the sun and help retain warmer temperatures in the vicinity once temperatures fall.
In terms of the soil or growing medium, peach trees need this to be deep, fertile and rich in organic matter. It should be moist yet well drained, neither drying out entirely in summer nor becoming waterlogged during the colder and wetter part of the year. These trees will tend to suffer in shallow or light soils. Choose a good quality soil-based potting mix if growing in a container.
Peach trees can either be purchased as bare root plants without potting mix, or in containers. Bare root fruit trees are available during the dormant period from late autumn to early spring. Potted specimens are available from garden centres and plant nurseries all year round.
There are a number of different things to think about when choosing a peach tree for your property.
One important thing to think about is the size to which the peach tree will eventually grow. The cultivar and its rootstock will determine the eventual size of the tree. Peach trees are usually grafted trees, with a particular scion grafted onto a rootstock base.
If you are growing in a container or a smaller polytunnel or other garden area limited in size, it can be a good idea to choose a dwarf variety.
The scion on a grafted plant determines the characteristics of the fruits, and this is something else you need to think about before making your decision. Fruits can differ in their size and sweetness from one variety to the next. And fruits can ripen at different times. So consider these factors too when making your choice.
Another thing to think about is the form that you wish your tree to take. Peach trees are often fan trained as training into this shape increases the yields of fruit.
You can train a young tree from scratch but if you wish to have a fan trained peach, it is far easier to select and purchase one that has already been fan-trained to begin with.
While you can purchase pot grown peach trees at any time of year, it is best to plant peaches during the dormant period, between November and early spring. This is true whether you have decided to purchase a bare-root or pot grown specimen.
If you are planting a peach tree in the ground, it can potentially be grown in any suitable sunny, warm and sheltered space. But it will do best planted against a south-facing wall.
Make sure that you place the tree at least 30cm away from the base of the wall, however, and be sure to amend the soil to ensure that it is rich and fertile as well as moist and free-draining.
For a fan-trained tree, remember that you will need around 3.6m of horizontal space along the wall, and should attach the needed support wires before planting.
Dig a planting hole, large enough to accommodate the roots with space to spare, and place the new tree within the hole. Firm the soil back around the roots, angling the tree so that it leans slightly backwards towards the wall/ support structure.
After planting, water in well and add an organic mulch around the new addition, surrounding but not touching the base of the trunk.
If you are planning to keep a peach tree in a container, make sure you choose one of sufficient size – at least 45cm across or large enough to accommodate comfortably the existing root system. Remember that dwarfing varieties will do best in pots.
Add some soil-based growing medium to the base of the container you have chosen, place your peach tree into the pot, and add more of the growing medium around the sides of the root ball. Mulch around the top and, of course, water in well.
Peach trees are not particularly challenging to care for but there are a few things to bear in mind to make sure that the peach tree remains healthy and provides a harvest of delicious fruits each year.
It is extremely important to water your peach tree well and ensure that the roots do not dry out completely at any point. During the growing season, you should water almost every day, reducing water given during the dormant season.
Remember that the wall or fence against which peach trees are placed can cast a rain shadow, and this may mean that even when it rains, peach trees growing outside as fans may still need additional watering through the summer months.
Of course, in a polytunnel, you will be responsible for providing all the water that the peach tree needs. Remember that plants in containers will dry out more quickly and so usually require more frequent watering.
A good, potash-rich, organic mulch will help to retain soil moisture and will help feed your tree. Chopping and dropping plant material like comfrey for example is a popular sustainable strategy for many fruit trees – peach trees included.
Trees growing in containers will additionally benefit from the provision of an organic liquid plant feed every couple of weeks through the growing season. A comfrey tea can be ideal for this purpose, for example.
A polytunnel can give some frost protection to a peach tree while it is in bloom. But bear in mind that you may still have to provide extra protection against frost in an unheated polytunnel since peach trees can flower as early as February when grown undercover and these flowers are vulnerable to frost. This is something you need to bear in mind when deciding precisely how and where to grow them.
You can protect peach trees with a layer of horticultural fleece or hessian supported on canes. Or, if you are growing a peach tree in a pot, you might move it into a warmer and more sheltered location or indoors during the crucial time period.
Since peaches flower so early in the year, it is unlikely (unless you keep your own bees) that there will be enough pollinating insects about to pollinate them. To pollinate by hand, on a sunny day, take a small brush and gently press the bristles into every flower. Do this on several afternoons and you should get some fruit.
When fruits appear, these should be thinned to give a final spacing between fruits of around 15cm. Remove any small or misshapen fruits when they are around the size of your fingernail. Keep an eye on fruits and if necessary, protect them from birds and other wildlife.
Most peach trees also need pruning to maintain size and are also pruned to maintain shape if they are grown as fans. However, some compact varieties will not need much pruning, if they need any at all.
Peach trees that do need pruning should only ever be pruned in spring and summer, to minimise the risk of infection with silver leaf and bacterial canker. Newly planted specimens are typically pruned after their buds open in the early spring. Established specimens are usually pruned in summer, after they have fruited for the year, while fan trained trees may also be pruned in the spring.
Peaches should be ripe and ready to harvest between July and September. Peaches will be ready to pick when they are fully coloured and the flesh close to the stalk feels soft. Cup each fruit in the palm of your hand and then lift gently.
You will need to harvest over a long period as not all the fruits will develop at once. Do not leave picked fruits uneaten for too long. Peaches are at their best eaten fresh, straight from the tree.
Some excellent varieties of peach tree to consider in the UK are:
'Bonanza'
'Crimson Fire'
'Garden Lady'
'Peregrine'
'Rochester'
Most common problems experienced when growing peach trees are ultimately caused by some problem with the environmental conditions or care.
For example, if the temperatures are too cold during blossoming time, or pollination was not taken care of, there may not be any fruits.
Fruits may also fail to ripen if there is not enough sun or temperatures are too low, or if there was a lack of water. Overwatering or wet weather conditions can cause fruits to split.
Sometimes, pests like birds and squirrels may damage or eat the fruits before you get the chance to harvest. Growing undercover, of course, makes these things easier to control.
If you decide to grow a peach tree in a polytunnel, consider adding thermal mass for temperature regulation and to improve the conditions for these heat-loving trees. But ensure adequate ventilation to make sure humidity is not too high and to give access to pollinators if these are around.
For best results, it is a very good idea to look into the idea of fruit tree guilds. Adding a guild of companion plants around a peach tree can help to ensure it remains healthy and potentially increase yields.
Petre, A., (2023) 10 Surprising Health Benefits and Uses of Peaches. Healthline. [online] Available at: https://www.healthline.com/nutrition/peach-fruit-benefits
