Similar to Apricot tree, Peach tree is one of the best fruits to grow in a greenhouse. It needs protection from winds and rains as well as warmth for flowering and fruit-ripening stages. Whether you are growing Peach tree outside or inside, you probably dealt with the situation where peaches on tree won’t ripen.
Although the most common reasons why peaches on tree do not ripen are insect damage or lack of water and nutrients caused by skipped thinning, other reasons include lack on light and genetic inability to produce ripe fruits. Let’s have a look at each problem in more details and I will also try to offer a solution.
1. Insect damage
Young peaches are perfect hosts for two insects: plum curculio and oriental fruit moth. Plum curculio is a snout beetle that attacks fruit trees in early spring and continues to damage the fruit throughout the season. Although it has only one generation, plum curculio larvae tunnel into the developing fruit resulting in inedible peaches.
Oriental fruit moth is one of the most serious insects for peaches. It attacks the your shoots and stone fruits. It has 4 generation but can be up to depending on location and the second one which are small, grey adult moths attack green or ripening fruits.
The damage from either of these insects slows down the development of ripening fruits and can eventually lead to falling of green peaches of the trees. To prevent this, spray peach trees as soon as the fruits start to set. You can use Imidan or Permethrin.
The first sing of insect damage are holes in the plant leave. Although greenhouse does a great job in protecting crops from animals that like to treat themselves to tomato fruits, for example, some insects can still make their way inside the structure.
However, to get rid of some bugs all you need to do is to use hose pipe or spray plant with insecticidal soap solution. So, if you have taken all the measures to control pests in a greenhouse or outdoors, but peaches on tree still won’t ripen, you might need to thin out the tree branches.
2. Tree branches are overloaded with fruit
To grow peaches to full size and ripen them, each fruit has to receive an equal part of water and nutrients. That is why you need to thin out branches. Aim for 6-8 inches spaces between fruits, so ideally you should have one peach every 6 to 8 inches.
Tree branches that bear unequal amount of fruit are not going to provide each peach with a right amount of water and nutrients. It also leads to tree giving out its resources to ripen fruit, so the tree is more prone to diseases and insect attacks.
3. Not enough light for the developing fruits
It is also necessary to prune the branches regularly to thin out the center of the tree. That way peaches will receive plenty on sunlight and ripen into nicely colored fruits. If you are growing peach trees in a greenhouse, double check the lighting requirements. It is vital to orient a greenhouse properly, so if you are not sure how to do it, check out the guide on how to set up a greenhouse.
Although your tree might be overall healthy and strong, if peaches don’t receive adequate amount of sunlight fruits won’t ripen. So, when planting a peach tree you need to position it north to south. Prune peach trees right now if they are tall and crowded.
4. Tree is genetically incapable of producing ripe peaches
If you are spraying and thinning peach trees regularly and fruits receive enough sunlight, the reason why peaches won’t ripen is that the tree is not able to produce ripe fruits. Most of the time it happens when peach trees are grown from seeds.
It can turn out that the tree that you have in your garden or greenhouse is actually a seedling. If that is the case, it can be not producing fruits because of genetic inability. That is why when buying a peach tree it has to be grafted from a known cultivar.
The only way to check it for sure is to buy a peach tree from a trusted seller and plant it. If the tree brings fruits in 3 years and you followed the guidance above, it means that you just came across a bad tree in the first instance.
Good varieties of peach trees to grow in the garden are Redhaven, Reliance and Riga. If you have a polytunnel or a greenhouse, you can grow Frost, Ice Peach, Red Heaven. Other well established peach tree varieties for greenhouse growing include Peregrine, Duke of York, Rochester and Bellegarde.
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