When it comes to Hawai’i, most people conjure up images of exotic tropical fruits, growing abundantly across the islands. Few even consider the fact that many fruits from the mainland can grow quite well in the tropics as well. One of those fruits is the grape.
Grapes are grown in Hawaii as well as other tropical regions, such as SE Asia, Nigeria, the Carribean, Florida and beyond. Many of these spots have found that grapes flourish in the upper elevations. With varieties such as Isabella or Muscat, grapes can also grow at warmer, lower elevations.
In order to be successful with growing grapes in the tropics, one must employ certain practices in order for the grapes to thrive. Let’s dive a little deeper into what it takes to grow grapes in the tropics.
Related: When growing grapes, you’re going to need a good pair of pruners. Why not get yourself a pair of one of the best and have it last a lifetime!
How to Grow Grapes in the Tropics
In short, to grow grapes in the tropics you need well draining soil with a well balanced PH. Locations Plant a rooted cutting of a favorable variety and plant with some sort of trellised support. Add a heavy mulch. Certain varieties can fruit as much as 2x’s per year.
That’s a pretty simplistic breakdown on how to grow grapes in the tropics. Let’s break it all down a bit more to empower you with the knowledge and confidence to grow grapes where others will tell you that it can’t be done.
Tropical Grape Varieties
It all starts with what variety of grape you plan on growing. For the most part, grapes that are grown in the tropics are table grapes, but in some areas, varieties can be chosen that make good wine grapes.
|V. Vinifera||Merlot||V. Labrusca*||Isabella|
|Red Flame||Orlando Seedless|
|Thompson||*Currently growing in Hawaii below 2000’||Southern Home|
|Black Beauty||White Malaga|
|Big Red||*Currently grown in Honolulu and Kona||Centennial|
Research on which variety grows best is still being conducted. By choosing a few different cultivars for your area, you can better determine which one would be the right fit for your growing zone.
Depending on the variety you choose, grapes can be grown in almost any climatic condition. In Hawai’i grapes have been grown in Honolulu, Kona and Pepeekeo on the east side of Hawai’i island. These are all lower elevation locations, ranging from dry to wet.
Of course grapes can grow at higher elevations that mimic temperate climates such as Kula on Maui or Volcano in Hawai’i, but what we are really excited about is the opportunity to grow grapes at lower elevations that would be considered more tropic in Nature.
When we say lower elevations, we mean 1000’ to 2000’. Below 1000’ and the temperature starts to get too warm to encourage proper growth and fruiting of the vines.
Grapes grown in drier areas have the ability to control watering and induce dormancy. This allows up to 2 harvests in one year! In the wetter parts of the islands, grapes have an evergreen growth pattern and produce one crop per season.
Success greatly depends on choosing the proper cultivar for your area. Refer to the table above.
Propagating grapes in the tropics is similar to that in more temperate climates, but for most people, finding grapes in the first place is the challenge. The best chance for obtaining material to propagate grapes is to contact your local chapter of the Hawaii Tropical Fruit Growers.
Once you get the material you need, it’s time to get propagating. Grapes are primarily propagated through hardwood cuttings. The main thing you want to do is find a branch that has at least 2 nodes available and cut a ½ inch below and ½ inch above each node, remove all of the leaves.
When placing the cuttings into a moist, well draining soil mix you want to make sure there are at least 1-2 nodes below soil level and 1-2 nodes above soil level.
Ensure that the soil stays moist and within 2 weeks to 2 months your cuttings should begin to root.
When it comes to soil, grapes don’t need much. Well draining soil with a pH slightly less than 7 is ideal for growing grapes. Lucky for us, that’s the characteristic of many hawaiian soils. There is no need for highly fertile soils. In fact, if the soil is too fertile the grapes put out excessive vegetative growth at the expense of fruit production.
The most important thing to do to prepare your soil is to clear it of weeds and let it sit fallow for a few months to kill any bacterias or disease that may be present in your soil. Once you have done that you are almost ready to plant. First you have to get that trellis in place.
While grapes can be trained to grow as a bush without any support, trellising help increase fruit production for your grape vines. In the backyard homestead, I like to have grapes utilize an arbor that fits somewhere in my food forest as an attractive garden feature.
If you have more land or just interested in utilizing more conventional trellising, you can install a trellis with T-supports similar to that you would see in a winery. Each T-support shall be placed 28’ from each other and connected by 12 gauge high tensile wire.
When it comes to pruning your grapevine, it is important in Hawai’i to prune the grapevine to provide sun protection for the fruit. I like to be sure there are a few leaves growing above the fruit. I will clear out any other leaves that are around the fruit, but are not providing shade from the sun.
The tool that I really like to use when it comes to pruning my grapes is my Japanese Hand Pruners. These pruners are the industry standard for pruning any type of fruiting plant, especially grapes where close quarter pruning is the norm. As long as you give these pruners proper care, they will last you forever.
When fruit sets, it is also important to thin the amount of grape bunches to ensure full ripeness of each bunch. Make sure the fruit is well spaced from one another so that it has room to grow and fully form.
When it comes to fertility, it is important to get a soil analysis to determine what your vines require. For the most part, grapes in the tropics do not need much added fertility. In fact, an application of deep mulch around each vine will be enough in most cases.
If you do add fertilizer, a balanced fertilizer of 6-6-6 or 8-8-8 should be sufficient to provide the fertility that your grapevines need in order to thrive.
Pests & Disease
Knowing what pests and disease affect grapes in the tropics will be the difference between success and failure. An area with low humidity and good airflow will be less susceptible to pests and disease than an area with high humidity and stagnant air. Sighting the location of where you plant your grapes is one of the easiest ways to deal with pests from the start.
- POWDERY MILDEW – This is a very common problem in Hawai’i. By planting your vines in a spot with good airflow you can almost eliminate this problem from the get go. If it does become an issue, an application of neem oil or sulpher works best as well as pruning the vine to encourage airflow.
- DOWNY MILDEW – This fungus tends to occur during the vegetative growth cycle following heavy rains. Best practices are to have good field sanitation, eliminating any pruned leaves as this is where the fungus finds a home and gets spread to your vines.
- TRUNK CANKER – This problem is caused by unsanitary pruning practices. Taking care while pruning, a good fertility program and irrigation can help vines overcome this issue.
There are a few other pathogens that affect grapevines in Hawai’i and the tropics. The best thing to do is practice good horticultural practices by keeping a clean growing environment for your vines.
When fruit does set, the most important pest to worry about are birds. By wrapping the fruit in fruit wrapping bags or newspaper, you can ensure that you will have a crop when it comes time to harvest.
Hawai’i is blessed with optimal weather conditions that allow grapes to produce fruit two times per year, sometimes three!
It is recommended to get special tools such as a refractometer to measure the soluble solids of the fruit. I have mostly grown table grapes so I just use my taste buds to determine if the fruit is ready to harvest.
Simply pick a grape off the vine, insert it into your mouth, take a bite and see if it tastes nice and sweet to your taste buds. If it tastes a little off, it may need more time. Simple as that.
There you have it, grapes in the tropics. Most people don’t even consider the idea of growing grapes in the tropics, but as you can see, it has been done with much success. I encourage you to get outside of the box when considering what to grow on your homestead, you might be pleasantly surprised.
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