Farm Report: September 2003

Each day here at the Research Farm is a learning experience, and we love to share it with you. The latter part of August has brought a welcomed reprieve from the heat wave we endured most of the summer. The summer rains have finally graced us with their presence, and it seems obvious to me that the beneficial effects of natural rainwater are greater than those of irrigation water alone.

Have you ever witnessed the tragic decapitation of your glorious sunflower heads? Perhaps "tragic" is a bit dramatic, but it certainly can be disappointing. This year we have seen this phenomenon occurring in our sunflower trials. After some close observation, we discovered the culprit— the head clipper weevil (Haplorhynchites aeneus). The small (approximately 8mm from the tip of the snout to the rear of the abdomen), shiny black weevils emerge in mid-July and are generally found on plants for a two to three week period. The flower head's pollen and nectar serve as food sources for the females, who lay an egg in the flower head after making a series of punctures in a circle around the stalk, usually just above the uppermost leaves. This causes the head to girdle and fall to the ground. The cream colored, grub-like larvae develop and over-winter in the fallen heads. The damage to our crop occurred mostly in the field margins and has not been devastating to the entire crop. If you see this happening to your sunflowers, be certain to pick up any fallen flower heads to eliminate the larvae inside the heads. This should help decrease the presence of the head clipper weevil the following season.

Another phenomenon we have seen here at the farm and in our home gardens is blossom drop on tomatoes, specifically the heirloom variety Brandywine. Blossom drop is when blossoms whither and fall to the ground before fruit is set. While some sources suggest this can occur when nitrogen levels are either excessive or deficient, the majority of sources I consulted attributed consistently high temperatures as the primary cause. High temperatures were defined as daytime temperatures greater than 90 degrees F, and/or nighttime temperatures greater than 70-75 degrees F. Several Agricultural Extension Service websites also noted a higher incidence of blossom drop in some heirloom varieties. Despite enduring several contiguous weeks of daytime temperatures in the high 90s, several tomato varieties in our fields have shown excellent fruit set: Burbank, Ropreco Paste, Roma Paste, and Peacevine Cherry to name a few. The earliest variety (almost 3 weeks before any others!) to ripen here was Gold Nugget, a cherry-sized, bright yellow tomato that we plan to offer in the near future.

In our other trials, the direct seeded brassicas are outperforming their transplanted counterparts in their vigor and robustness. The onions (the Walla Walla and Valencia varieties are especially impressive) and early potatoes (Yukon Gold and Red Sangre) will be harvested soon. In our flood field, the Discovery Mix sunflowers are topping out at 18 feet tall! Our replicated trial of 'Genovese' basil gave us a generous first harvest of gorgeous leaves that the staff quickly made into deliciously fresh pesto. Our zucchinis and cucumbers are beginning to slow in production under the pressure of the prolific squash bugs, while the okra is just beginning to produce vibrant red (Red Velvet) and green (Star of David and Mammoth Spineless) fruits. The Oxheart carrot crop is nearly ready for an initial seed harvest, during which we will cut the flower heads containing mature seed and place them in our seed room for drying. Recently, we also planted our fall spinach, chard, radishes, and another round of culinary herbs.

On the 16th and 23rd of August, we hosted this year's two public farm tours. As always, the staff at the Research Farm had a wonderful time meeting with other passionate and interested gardeners and sharing with them the Seeds of Change mission and what our work here entails.

Cheers,
Jordan Rainwater, Research Associate
and the entire staff at the Seeds of Change Research Farm