Coastal Southern California, sunset zone 22, is generally not considered an ideal grape growing climate.  Nevertheless, we have had great success with a few grape varieties over the last decade and a half.  Between my friend across the street and I, we have grown Black Monuka, Fantasy, Glendora, Niabell, Eastern Concord, Canadice, Flame, Perlette, Interlaken, Einset, Marquis, Neptune, NY47616, and Jupiter.  More than once during a shift at the CRFG booth at the Green Scene I get asked to recommend what is the best grape for our climate, and always start with Jupiter.

We don’t get a whole lot of annual heat or even a lot of sun during June and July.  LIving not far from the coast, our summers are dominated by what SoCal locals call “June Gloom” for a large part of the early summer, with overcast skies until early afternoon, if the sun bothers to come out at all.  We also have higher humidity than communities further inland. Because of the mild weather, we are blessed to not need an air conditioner, but that also means successfully growing heat-loving popular table grapes found in the grocery stores, which is completely out of the question, especially growing them organically.

About five years ago, I planted, on the recommendation of a member of California Rare Fruit Growers, to try Jupiter, a purple, seedless, semi-crisp grape.  It produced a light crop after only 1 1/2 years in the ground, and I liked it so much, I planted a second one that same winter.  Jupiter Grapes are ripe when they are a dark purple on the skin and green inside, with a crisp sweet taste.  As far as my grapes go, Jupiter is the Goldielocks of grapes in the backyard.  It is not too small, not too sweet, not to tart, it is just right.

So far, we have not had any diseases issues on the Jupiter variety, including no powdery mildew, which often plagued my flame seedless most summers.  The humid conditions here aggravate the powdery mildew issues. Last summer we had very little sunshine, and it performed fabulously.   It is a moderately vigorous grower, which is much appreciated by the chickens who get many of the branch trimmings if the vines start to get out of control.  The Jupiter grapevine is a hybrid of American and European grapes, developed and patented by the University of Arkansas in 1998.

Jupiter is normally the second grape variety to ripen at my house, just a few days to a week or two behind Canadice. This year we picked our first few clusters on July 1st.  Most of the Jupiter grapes should be ready within the next few weeks.  Right now, some berries are still reddish.  I am aware that other parts of the country don’t start picking these until much later in the summer, but I would consider it an “Early midseason” variety of grape.

My second Jupiter grape vine isn’t planted in the best location and only gets half-day sun, at the very best.  Never the less, it still flowers and produces just fine, just slightly later than the one near the veggie garden.  It actually works out well for us, helping to stretch out our harvest.  If I had to pick one seedless table grape variety for coastal Southern California or similar cool climate, I would have to say Jupiter is the best grape.

Update: Since posting this, I have a newer grape that I like the flavor of even more, Petite Jewell. One of my favorite resources on growing grapes is book by Lon Rombaugh called the Grape Grower. He started a blog and maintained a website where he sold grape cuttings..