Once you’ve enjoyed fresh soursop, it’s easy to fall in love. If you can’t get enough of this fantastic fruit, you might even be considering growing soursop in your garden.
As with all plants, you must have the right climate to grow this tree, but if you live somewhere that doesn’t experience frost, you’re in luck. A flavorful harvest is well within your grasp.
Are you ready to learn about growing soursop? Let’s go.
What is Soursop?
So what is soursop, exactly?
Soursop (Annona muricata) is an evergreen tree closely related to cherimoya (A. cherimola), sweetsop (aka sugar apple A. squamosa), custard apple (A. reticulata), and monkey (or pond) apples (A. glabra). It is native to tropical areas of the Caribbean and the Americas. Soursop is a broadleaf tree that reaches up to 30 feet tall and is a rapid grower. Under the right circumstances, the tree will give you a crop of fruit in as little as three to five years from a seedling.
The fruits have a citrus zing to them, but they also have the sweetness of strawberries or mangoes and the crispness of an apple. The custard-like consistency of the pulp lends itself perfectly to making ice cream, puddings, smoothies, and other treats. It can also be used in savory dishes such as soup.
It’s also got vitamin A and C, and a load of other beneficial goodies.
Also known as graviola, prickly custard apple, or guanabana, soursop fruit is often eaten raw by scooping out the flesh of the spiky fruit cut in half, though some people may find it too acidic like that.
I was gifted a book many years ago that listed unique plants to grow. Soursop was one of them. I have to admit it was something I hadn’t heard of before, but over the years I have come to love this exotic fruit tree and the flavorful, spiky fruit it produces.
Best Forms and Types of Soursop
There are a number of forms and types of soursop. In many regions, they are divided into sweet, standard, and very sour. They can be further divided into those with fiber and those that are fiberless.
Remember, though, that “sweet” is a relative term. Even the sweet types have some acidity.
This is a sought-after variety because as the name suggests, the flesh is smooth and creamy, rather than fibrous. The tree grows 16 to 32 feet high and needs consistent temperatures above 41ºF.
It’s self-pollinating and only needs moderate water, but don’t let the soil dry out too much. It isn’t drought tolerant.
This variety isn’t cold tolerant at all and should stay well above freezing. It prefers sandy to loamy soil. Basically, it likes tropical environments like Indonesia where it hails from.
Another reduced fiber variety, though this is not a prolific fruiter. The flesh is extremely creamy and it is an easy-peel, sweet fruit.
This is a large variety, so each fruit gives you more flesh. It’s a hybrid that was described in 1920 when it was introduced in Florida as the most prolific soursop growers had ever seen.
The skin is blue-green.
As the name suggests, this variety produces giant fruit in abundance, with each one reaching up to 15 pounds in weight. The tree grows up to 30 feet and the flesh of the fruit is low in fiber. If you plant this variety, be careful of the heavy fruit falling.
How to Plant Soursop
Soursop is a tropical tree that needs heat and humidity. It will grow in zones 10 to 13. Alternatively, you could try to grow one n a greenhouse that is warm and humid. They will grow successfully in containers, but you will need to manage the size through pruning.
Soursop is one fruit tree that doesn’t take forever to start growing a big, bountiful harvest of fruits. In fact, growing soursop from seed is the preferred method for propagation. That’s handy given the number of seeds in some of the fruits.
You will need a fresh soursop fruit to remove the seeds from. There are few varieties that have seeds that can be stored for months and still germinate.
Remove the seeds and wash them gently in lukewarm water. Place in lukewarm water and soak overnight. Don’t soak for longer than 12 hours.
Plant in a seed-raising mix about 1/2 inch deep and keep moist. You should see germination within a month but the average is more like two weeks. Fresh soursop seeds have at least a 90 percent germination rate according to the College of Tropical Agriculture and Human Resources at the University of Hawai’i.
Leave the plant inside for at least six months if you’re able to. This is one fruit tree that is very sensitive to cold weather, especially when young. A frost will likely be the death of it and cold weather may make the leaves fall off.
Air layering and grafting is also possible, but for the average home grower, starting by seed or transplant is the way to go.
I temperatures fall below 0ºF, the soursop will die, but any amount of frost is detrimental. Even a few degrees of frost will cause leaf drop and can kill any fruits. When temps drop down into the low 40s, the tree will likely drop its leaves. If this happens enough in one growing season, it can kill the tree.
If breadfruit grows well in your area, soursop likely will too.
In the US, you’ll mostly find soursop growing in Hawai’i and Puerto Rico, but it can survive parts of southern Florida so long as it is planted in an area where it is protected from strong winds.
A soil pH of anywhere between 5.5 and 7.5 is fine. Soursop prefers sandy soil that drains well, but can retain moisture. Standing water will kill soursop quickly, but a little bit of drought is tolerated. This is the most drought tolerant of all plants in the genus.
Plant in full to partial sun; just make sure the young tree isn’t too shaded or in a cool part of the garden. Protect it from strong winds so stake it if necessary.
When you have planted the soursop outside and the trunk is at least 3/4 of an inch thick, prune the tree back to about 25 to 30 inches in height. Allow new shoots to grow and choose the strongest vertical shoot to be the central leader.
Choose up to five other shoots to be the branches. These need to be horizontal so you can always use clothes pegs to wedge in between these branches and the central leader.
This may seem fiddly, but it is the best way to get a nicely shaped soursop tree. By all means, plant and see how it grows and prune to shape later if you prefer.
Caring for Soursop
Mulch your soursop tree to help maintain moisture in the soil. The root system is quite shallow so needs all the help it can get in hot weather.
Feed with a balanced fertilizer twice a year in both spring and very early fall. For best results try the following schedule:
- 1st year feed 1/4 pound of fertilizer per feed. Use an NPK of 10-10-10.
- 2nd year feed 1/2 pound of fertilizer per feed.
- 3rd year on onwards, feed 1 1/2 pounds of fertilizer per feed.
Freshen or add to the mulch a couple of times a year if it is starting to thin out too much.
Water regularly, but don’t allow the soil to become soaking. Ensure it drains away well. If you have soil that doesn’t drain well, seek out a soursop tree grafted on to pond apple. This may help.
Repeat the pruning method above in the second year if desired. Cut the central leader back by about 1/3 and choose the best horizontal branches, ensuring they maintain the shape you’re after.
Around year three to five, you should see the yellow-green blossoms. They can form anywhere on the branches or trunk. In that first year of blossoming, consider hand pollinating, but it isn’t compulsory. It might just give the fruiting a head start. High humidity and moderate temperatures in the 70s and 80s improve pollination.
You don’t need to prune mature plants except to remove dead or diseased wood.
Common Problems and Solutions for Growing Soursop
Anthracnose is a fungal disease caused by the pathogen Colletotrichum gloeosporiodes. It causes irregular yellow or brown spots on leaves that expand and darken over time. This can affect your harvest and overall plant health. Read our extensive article on anthracnose here.
This disease affects smaller twigs and branches. You will see a telltale pink growth on the bark. The infected parts will die, so cut them off and burn them. Treat with a copper-based fungicide to prevent more infections.
Armillaria Root Rot
Armillaria root rot is a disease caused by the fungus Armillaria leuteobubalina which attacks when plants are sitting in soil that is too wet. The best thing to do is avoid it because once it starts your soursop plant will struggle. Don’t overwater, allow the soil to dry out well between watering, and plant in well-draining soil to begin with.
Fruit rot is the result of the fungal pathogen Gliocladium roseum. Plants infected with this disease will begin to rot starting at the top and will gradually turn black across the rest of the fruit. The interior may rot as well.
Remove any rotting fruits and treat the tree with a fungicide containing Bacillus subtilis like Cease.
Rust is a fungal disease caused by Phakospora cherimoliae that results in orange-red growth on the leaves of the tree. Read our guide to identifying and dealing with rust.
This disease can be caused by a number of different bacteria, but usually Pseudomonas species. It causes fruit to rot after it has been harvested from the tree. Treat it with a fungicide like Cease, mentioned above.
Carpenter Moth larvae
These destructive pests bore into the softwood of the soursop tree. This disrupts the flow of nutrients and you will see this with the struggling appearance of the infected branch. If you suspect these larvae, cut the infected part off and burn it.
There seems to be few plants scale won’t infect. See our article here to learn how to identify and treat scale.
Mealybugs will suck the sap and juice from leaves, tender branches, and even the fruit. The fruits will turn yellow and wilt before they get a chance to develop.
There are sprays that control mealybugs, but see what’s available in your area. Try to deal with mealybugs before they increase in numbers.
Fruit flies such as Ceratitis capitata, and Bactrocera cucurbitae and B. dorsalis lay eggs inside the fruit, rendering them inedible. Neem oil and insecticidal soap are effective treatments, though you’ll need to reapply at least every other week for a few months.
Harvesting and Using Soursop
One good thing about soursops is they don’t all ripen at the same time. Only pick the fruit if you are going to eat or add to recipes straight away or within five days.
Wait until the spines stand up and the fruit loses its shine. It should go from dark green to a lighter yellow-green. Let the fruit sit for four or five days before eating. The fruit will further ripen and become sweeter. At that point, the skin should have a slight give under pressure.
Don’t let the fruit fall off the tree! Once it falls, it is overripe and will smoosh and splatter as it lands on the ground.
The seeds are considered toxic so remove them before you eat raw, juice or add to recipes.