French Laundry Culinary Gardener Aaron Keefer Speaks on the Generous Tomato

I feel the tomato is the most generous plant of the summer. It always amazes me at how much product can come from a seed the size of a pencil head!

Here in Napa Valley, we have mild winters that are governed by the Pacific Ocean. We occasionally get frost at night, but during the day the frost yields to temperatures in the 60’s and 70’s. Because of these cold nights, we have a hoop house that acts as a buffer for the climate. The hoop house is designed to retain solar heat, giving us temperatures much higher than the day’s high. On sunny winter days, the temperature in the hoop house can reach the high 80’s even when it is 50 degrees outside! To best utilize the hoop house, we keep its sides and ends open during the middle of the day to encourage ventilation and close the hoop house mid-afternoon to capture the last of the day’s solar energy. This allows us to get a good head start on the summer crops.

We start our tomato seeds around February 15 on heating pads so the plants never dip below 45 degrees Fahrenheit. After a few weeks of growing these starts, they are transplanted into larger containers where we let them grow to be 18 inches tall before we plant them in the ground. We aim for an outdoor planting date of April 15, that way there is little chance of a late frost that will damage the first set of flowers and drop the fruit. Tomato plants that go through a frost might survive but will usually be slowed enough that a smaller plant planted after first frost will outperform the first tomato in the long run.

Once the plants are in the ground, there needs to be a plan for the massive weight that will come. Non-determinate tomatoes are vines that can stretch for days, and they need to be supported off the ground so that the fruit does not become diseased. We employ a trellising method called the Florida weave. Under this model, we pound 8 foot t-stakes 3 feet into the ground at 8 foot intervals and weave twine in a figure eight pattern around the plants, tying then all together along with the line of posts. Every week, or with every 6 inches of growth, we repeat the weave so that the tomatoes stay supported even when there are hundreds of pounds of vine and tomato fruit between each post set. This trellising method also benefits the tomato plants by allowing for shading, which cuts down the number of sunburnt fruit.

This year, we are growing 52 varieties of tomatoes and our yield is amazing! The peak of our season lasts 4-5 weeks but if the rains hold off, we can harvest tomatoes until mid-October here in Napa.