One of the frustrations of CSA farming is the mismatch between supply and demand in the summer. Most years, the peak production of summer crops like tomatoes and peaches falls almost exactly during the long summer break when most kids are out of school and families tend to leave town. Like most CSAs, Terra Firma sees a seasonal dip in the number of subscribers receiving boxes every summer, and a corresponding increase when schools open again for their fall term.
But historically, September was the low-point in our farm’s production. Summer crops were finishing up and our fall crops were not yet starting. For a while, we tried to “speed up” Autumn, planting winter crops earlier in the summer. Climate change has increasingly made that impossible, as some of our hottest weather of the year often occurs after Labor Day.
Instead, we are now focusing our energy on extending Summer for another month, into October. This might seem like a no-brainer, as even the cooler parts of Northern California are pretty warm in early fall. But the problems we have this time of year are not simply temperature-related.
Over our long summer, pests and diseases multiply and build up. And vegetable varieties that do nicely when planted in spring when it’s cooler don’t thrive when it is hot every single day of their lives. For example, Tomatoes or Summer Squash that grow beautifully in May and produce abundantly in July poop out when planted in July and may fail to produce at all in September.
So we have been on the hunt for new vegetable varieties that are better suited for the hotter world we live in now. And over time, we have found some. One example is the Zucchini we are now harvesting. “Desert” needs less fertilizer than older zucchini varieties, enjoys the heat, and is resistant to several common plant viruses spread by flying insects. We grew it for the first time last year, and it did so well that we added an extra planting this year in the hope of using it to extend our summer squash season — which used to end in early September — into October. (Apologies if you are “zucchinied-out”.)
We’ve also bolstered our roster of heat-tolerant Tomatoes. If you thought tomatoes loved the heat, you’re half right: they do need warm-to-hot temperatures to ripen and develop good flavor. But most varieties — especially heirloooms — do not pollinate in very hot weather. When we plant them mid-summer hoping to harvest in fall, the plants get big and beautiful, but very little fruit. And thanks to pests and viruses, much of the fruit is unsaleable.
Seed breeders have been working on this problem too. All the tomato-growing regions of the world are now experiencing longer, hotter seasons and more disease pressure. So in the past few years, they have been introducing “upgraded” versions of old favorite varieties that have been cross-bred for better tolerance to heat and diseases. We have been slowly and cautiously trying out these varieties — regular red tomatoes — in late plantings that we had given up on. Last year we had a bumper crop in September and even into October, and we’re hoping for similar success this year.
Perennial crops are a longer-term challenge. Traditionally, stone-fruit season ended in mid-September. But with climate change, most years it now starts early and ends around Labor Day. This is particularly frustrating given that the season for fall tree fruit doesn’t really start until late October.
Like their counterparts in the vegetable industry, tree-fruit breeders have been working on this problem, introducing a number of varieties of peaches and nectarines that ripen later. Unfortunately, just about every peach grower in California wants to plant them, and the trees are currently back-ordered until 2025. We’ve got some ordered, but once we plant them, it will still be several years before our first harvest.
If you’re just starting back up on your TFF CSA box again after a long summer break, you’ll have just a week or two of peaches before they disappear for the year. But you can look forward to a continued supply of tomatoes and summer squash, in addition to other summer favorites, for another month or more. And we’ll keep working to track down and try out new varieties to help keep your boxes full and fun.