Mandarin trees will have no fruit if they are less than 3 years old, if the flowers are not pollinated or if the tree is not getting enough sun. Mandarin trees grow fruit over the cooler months and will produce their best crop of fruit every 2 years. Mandarin trees will produce no fruit if they are not getting enough water or if the rate of nitrogen to potassium is too high.
Top reasons why there is no fruit on Mandarin trees
- Mandarin Trees aged less than 3 years
- It is the off year for your tree as mandarin trees grow the best fruit every 2 years
- Not enough pollination to set mandarin fruit
- Not enough sun to produce fruit
- Not enough water to grow mandarins
- Too much nitrogen
Top reasons why there is no fruit on mandarin trees and solutions
Mandarin Trees aged less than 3 years
Mandarin trees will need up to their third year before they will start producing fruit. The first crop of mandarins can be small and oddly shaped but as the tree grows it will produce more and better shaped fruit.
Mandarin Trees grow the best fruit every 2 years
Mandarin trees generally will grow a big crop of mandarins every second year. The year in between will produce less and smaller fruit or sometimes no fruit at all. If you have just moved into a house with a mandarin tree and you are not seeing any fruit, it might be the next year that it will grow fruit.
When planting new mandarin trees, it is likely that you will need to wait until the next year before it will grow a good crop of fruit. Unless the tree is advanced, it will usually need a year to settle in and grow a strong root system before it is ready to grow mandarins.
When we moved into our last house in Sydney there was a young mandarin tree that grew 3 mandarins successfully in the first year we were there. The next year there were no mandarin fruit and we had moved out before the tree was ready for the third year. The year we moved out was likely to be that mandarin tree’s best year for growing fruit.
Increase pollination to grow more fruit on mandarin trees
Mandarin trees will grow small white flowers which need to be pollinated. Pollination is where pollen is moved from one flower to another so your mandarin can grow fruit. Mandarins can be pollinated by other citrus types such as lemons but the mandarin fruit will often have more seed if this occurs.
Pollination studies have shown that mandarin trees produce different amounts of fruit and seeds depending on which tree they were pollinated by. A study was conducted by the American Society of Horticultural Science. They investigated the number of seeds and fruit produced by different cross pollinating partners of mandarins
The study looked at these Mandarin and Clementine varieties:
- Nules
- Fina Sodea
- Marisol
- Fina Clementine
- Afourer
- Tahoe Gold
- Gold Nugget
The study found that when Fina, Marisol and Fina Sodea self-pollinated their fruit production was very low or almost near zero. The most fruit was grown when two Clementines, Nules, Fina Sodea and Afourer were cross pollinated.
- Seeds per fruit averaged 5-12 Afourer mandarin x Clementines
- Seeds per fruit averaged 23-32 for Clementines x Afourer Mandarin1.
My advice is to plant two mandarin varieties close together if you have the room otherwise you may need to expect a few more seeds in your mandarin than those grown in the shops.
More sun will produce more mandarin fruit
Mandarin trees will grow more fruit when grown in full sun so if your tree is getting too much shade, this could be the cause of low fruit production. If your mandarin tree is already in the ground, look at ways to give it more sun by trimming other trees and shrubs around the plant.
Mandarin trees in pots can be moved into a sunnier position to encourage more fruit. Trim back excess leaves so the branches on the inside of the plant get more sun and will grow more fruit.
Regular water grows more mandarin fruit
Mandarin like all citrus trees prefers to have regular water and if they dry out too much at any time of the year the plant will not grow fruit. A mandarin tree will sense that there is not enough water around so will preserve what is there and not grow fruit.
Regular deep watering of your mandarin tree over summer and regularly checking the soil in winter is important for good fruit growth. Water the mandarin deeply up to 3 times per week in summer to keep the tree healthy and ready to grow fruit in the cooler months.
Mandarin trees grow most of their roots in the top part of the soil with small feeder roots growing in the top 12 inches. Mandarin trees can grow roots as deep as 24 inches so water them deeply so the roots at the bottom get water and the tree is encouraged to grow more deep roots to keep it stable.
Feed with a fruit fertilizer for more mandarin fruit
The balance of nitrogen to potassium is important for your mandarin to grow lots of fruit. High nitrogen levels are great for getting your tree growing and for setting it up with healthy stems and leaf growth. One your tree has established switch to a fertilizer that promotes fruit like sulfate of potash.
Fruiting fertilizers increase the potassium levels and send a signal to the tree to produce flowers and fruit. More flowers mean more chance of pollination and eventually more mandarin fruit.
The right time of year for Mandarin trees to grow fruit
The right time of year for mandarins to grow fruit is in the cooler months, starting from Fall into Winter.
Mandarins produce fruit in the cooler months, in the US this is anywhere from November all the way through to April. They will grow flowers in the Fall months and the fruit will set and ripen usually by winter.
Tips for growing more Mandarin fruit
Set the tree up for success by planting in good soil
Plant new mandarin trees into soil enriched with compost, aged cow manure, worm castings and pelleted chicken manure. Make sure the soil is free draining so the roots of the mandarin do not get too wet. This will give the tree a great start, help it to get established and grow a strong root system.
Use seaweed solution to encourage soil microbe growth
A healthy population of soil microbes will help your mandarin tree to grow lots of fruit in the long term. Water your mandarin tree with seaweed solution or worm juice every month in its first year. This will encourage healthy soil and the microbe will break down organic matter releasing nutrients for the plant.
Mulch Mandarins with tree mulch
Tree mulch is my favorite for citrus trees including mandarins. It works to keep weeds away, moisture in the soil and to feed the plant and soil as the soil microbes break it down. Worms will come to eat the organic matter and microbes to aerate and improve the soil.
No fruit on Mandarin trees – Summary
Mandarin trees are easy to grow if you follow the basics and set the tree up well with healthy soil, water it regularly and place it in a sunny position. Mandarin will produce their best crop of fruit every 2 years so be patient and if you are not getting fruit the first year the next year will be a winner.
References:
1Chao, C. T. (2005). Pollination Study of Mandarins and the Effect on Seediness and Fruit Size: Implications for Seedless Mandarin Production, HortScience HortSci, 40(2), 362-365. Retrieved Jun 19, 2021, from https://journals.ashs.org/hortsci/view/journals/hortsci/40/2/article-p362.xml
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.