Nothing Fancy. Basically, I have these 7 varieties potted in standing free draining mix which consists of premium potting mix, sand, pearlite, large pine bark chips and large hardwood chips. The ratio should favor the sand and hardwood chips, for the obvious reason that both will be the last to break down. Standing free draining soil; it doesn't matter how you get there, so long as you do. Dieback is common in fingerlimes, even grafted plants, and this is caused by waterlogged soil. If you are seeing dieback on your upper growth, water saturation is almost certainly the cause. Dieback occurs most in relation to excessive watering followed by drying off, which is why free draining soil is essential.
Update: I am now growing all my fingerlimes in a mix of coir, pearlite, and vermiculite. The mix is quite gritty.
I also apply a heaped handful of lime and water this in every year.
I have found the best mulch to be large decorative stones stacked at about 2cm or enough to completely cover the surface of the mix. This does not break down, allows nutrients to pass through effectively, and stops water perching as a consequence of hard hose watering. Gritty mixes are superb for finger limes and
will not dry out if you have your limes in adequate shade.I have each pot elevated with a simple setup of hardwood slats running between two concrete blocks. It's important to do this for drainage. The key to keeping finger limes happy and healthy will depend on two things:
A) very free draining soil
B) the right sun exposure conditions.
It might not come across in the photograph, but these plants receive filtered light at different intervals throughout the day, with the main sun exposure coming from about an hours full sun on either side of dawn and dusk. In baking heat, your finger lime will not do well. In total shade, it will produce less fruit. In their natural environment, fingerlimes occur as understory trees at the edge of forestry; the light cycle I provide mine seeks to mimic that as closely as possible. In the wild, they grow in deep loam extremely rich in detritus. Most Australian forestRy trees are hardwood.
It is important to keep your fingerlime in a wind-sheltered position as they are susceptible to wind scorching, and the flowers they produce will get stripped by strong gusts. If you have a carambola/starfruit, the effect of wind on flowers is similar between species.
On fertilisationGrafted trees should be fertilized with citrus fertilizer, though more frequently than standard citrus. The ones in my picture have a layer of pure composted cow manure spread over a layer of inch-thick, fine mulch. Basically, the reason I've done this is to encourage the right microbes into my mix. I will also add a few worms to each pot at some point, and have watered each plant in with a soil conditioning product called seasol., but any seaweed treatment is fine.
Once the plants are established, I will fertilize with standard granulated citrus fertilizer at intervals of two months. I have never had an issue with over-fertilization using this method. I do not know if this is true of non-grafted trees.
Important:
Foliar sprays of Epsom salts will increase yield and quality. You could also sprinkle a couple of teaspoons of this around the base of the tree and water in for the same effect.Do not overwater your finger lime. It will hate you for it.
About the fruitFinger limes are precocious when it comes to fruiting, yet are slow to establish a large root system. Plants struck from cuttings can generate fruit within the first year. Like most citrus, finger lime fruit gets larger in correspondence with the size of the tree That is, the bigger the tree, the bigger the fruit.This phenomena is more exacerbated in finger limes. This is also true of fruit quality; larger fruit will be considerably more appetizing, have juicier vesicles, and will not be turpy. I don't know why that is, just that it is.
Harsh sun exposure will cause woody spots in the fruit of finger limes. Because the tree is thorny, wind which blows the fruit about will inevitably cause said fruit to get 'spiked', This will also cause spot fouling. This is another reason to keep finger limes in a sheltered position. Fruit exposed to harsh sunlight will also bleach and will be less cosmetically attractive, and dry skin may dry out the pulp immediately beneath the affected area. Harsh light is likely to cause burning, and will result in leaf browning and a generally spindly, unhappy tree.
Finger limes will hybridize and cross readily; the flowers, while small and unpretty, are very attractive to native bee species in Australia. If you have a high presence of pollinating insects, and have a number of finger limes in close vicinity to one another such as I do, expect to get varying colored fruit
a lot if you intend to grow from seeds. If you want to keep your fruit true, you'll have to do what the song says--keep em' separated. It is for this reason also that you shouldn't keep a variety you consider to to be sub-par, or not to your liking, around. This is true of all varieties of Australian native citrus. The CSIRO has released two varieties of hybridized native limes. These are the red centre lime (also known as blood lime, which a mandarin fingerlime x) and the Australian sunrise Lime (this is a calomondin fingerlime x).The CSIRO has also developed a cultivated variety of the desert lime (Citrus glauca). In reality, finger limes could be crossed with any citrus.
Here are some pics of my new grove, most of these trees are very young.