Your Lime Tree Isn't Getting Enough Pollination: Here's How To Fix It

If you've been struggling to amp up the yield from your lime tree, despite it having a lot of flowers, chances are, your tree is not getting enough pollination by itself. Despite the tree being self-pollinating, and even after you've taken all the essential steps to grow and care for your lime tree, there could still be a number of reasons for the evident lack of pollination. This could range from bad weather, lack of natural pollinators, semi-optimal temperatures, or the tree's overall health. Nonetheless, you can lend your lime tree a helping hand (literally, in this case) using the method of hand-pollination – that is, manually transferring pollen from the anthers of the flower to its female receptacles — and enjoy more fresh limes a few months down the road. Even if your tree doesn't have a persistent problem with pollination, you can still adopt this technique if you want to boost your fruit yield to greater numbers.

Being part of the Citrus genus, mother nature has endowed lime trees (Citrus x aurantiifolia) with the faculties of self-pollination. What this means is that a single lime tree is enough to initiate pollination and fruit formation, thanks to the presence of both male and female parts in its flowers. You can contrast this trait against plants like apples, cherries, plums, or asters, which require at least two compatible plants to be close together for pollination. More often than not, the lime trees that grow outdoors have no problem because they're readily visited by bees. However, It's the indoor specimens that need a push, since pollinating agents like bees are not roaming around in your house to do the job.

Hand-pollinating a lime tree, although fairly simple, also requires some patience, and will make you appreciate the amazing work bees do to get those delicious lime tarts on your dining table. The first thing to keep in mind with this process, is doing it at the right time, since you probably won't find the anthers laden with pollen, as well as the stigma of the flower being receptive to receiving it, every hour of the day. 

Early morning is a good time though, and preferably on the day the flower has just opened up. Waiting too long can result in the entire bloom becoming too fragile and the stigma losing its receptivity as well. You can easily recognize the period of maximum receptivity in a citrus flower when you see its stigma turning extremely shiny, juicy, and bright yellowish in color. That's the perfect time for pollinating the flower.

To hand pollinate, take a small, fine paintbrush or a cotton swab, brush it gently against the anther to gather some of the pollen, and transfer this to the stigma of another flower. Selecting a stigma of a different flower will help produce a better fruit set. You can even do this with your fingers by gently tapping the pollen onto the stigma. Repeat the procedure with other flowers on the tree, as well as with flowers of other lime trees too, if you have them in your yard. Perform the entire process for a number of days to maximize the chances of pollination in as many flowers as possible. Just make sure to take extra care to be gentle throughout this activity, so you avoid damaging the delicate flowers on your tree.

A key thing to keep in mind when hand-pollinating your lime tree is to not lose heart when you see some of the flowers you have tried so hard to pollinate, drop off and die afterwards. Pollination is a numbers game, and citrus trees produce an enormous number of flowers, a lot of which are not going to survive. This phenomenon is a natural survival mechanism for the species, to increase the chances of fruit formation and the eventual seeds.

Moreover, apart from pollinating by hand, you can also take some steps to bring more pollinators to your yard and garden, particularly if your lime is growing outdoors and still struggling. Put a cap on your pesticide usage, as it is probably seriously affecting the pollinator population in your yard, especially bees. In fact, pesticide usage is one of the three most prominent factors behind the decline in the pollinator population throughout the world. Further, you can also grow some companion plants with your lime trees, such as lavender, borage, and marigold. These will not only come in handy for inviting pollinators but also enhance the aesthetics of your garden a few notches.