Growing Tomatoes as Cordons

In parts of the world where the growing season is short or there is a general lack of sunlight, tomatoes are often grown as cordons, which enables more of the available light to reach the fruit. In spite of being advised not to use this technique in the hotter parts of California, due to the risk of sunscald damage to the fruits, I thought that I would try it in the Owens Valley to see if I could increase my tomato plants' performance. Last year, I harvested only two red Brandywine tomatoes and was left with a huge crop of very green tomatoes at the end of the season.

This year I chose Pineapple, a large, yellow, low-acid, heirloom variety to see if there was a discernible difference between growing it as a cordon or the more traditional way.

Two closely matched 6” high plants were planted directly into the soil on April 22.  Growing conditions could not be matched exactly, since the shrubby one was slightly more shaded than the cordon specimen; otherwise, cultural conditions such as soil and irrigation were the same.  No covers or “walls of water” were used, liquid fertilizer was applied twice during the season, and the plants were not mulched, as they were grown adjacent to squash plants, and I wanted to minimize hiding places for squash bugs.

Method:  Cordon tomatoes are grown by choosing an indeterminate variety, which is then tied to a tall, sturdy stake and trained as a single stem by removing all shoots from the leave axils as soon as they appear. Flower clusters develop from the main stem between the leaves, and the general advice is to allow the plant to produce about 6 trusses before pinching out the leading shoot to prevent further vertical growth. The stake was placed on the west side of the plant in order to protect the main stem from the most intense afternoon sun.  The plant grew extremely well, and I had to be vigilant keeping it tied to the stake (using a soft tie which would not damage the delicate stem) and in removing the shoots which appeared and grew rapidly.  If left for more than a few days, their removal caused a large wound which could potentially result in the entry of disease.  Even with very little fertilizer, this plant soon reached 6ft and the lower clusters began to flower early, with about 5 flowers on each truss.   On July 19, I picked my first fully ripe 10.5 oz tomato from this vine. 

For the other plant, I staked and allowed it to sprawl over a 4-foot tomato cage made from field wire. No pruning was performed, and it soon made a thicket of healthy stems and foliage.  I picked the first fruit from this plant on August 9, but had 3.5lbs of green tomatoes remaining in early October.

As can be seen from the above table, the cordon certainly produced ripe fruit much earlier than the unpruned plant, and the individual fruits were considerably bigger - often in the 13 oz range, while those from the unpruned plant averaged around 6oz.  However, the cordon produced a much lower overall yield, stopped producing more noticeably during the very hot weather, and set far fewer individual fruit. Some of these issues could have been avoided by using better horticultural practices, such as mulch and regular fertilizer!

Although fruits on both plants suffered from some cracking, none was affected by sunscald in spite of having some very clear, hot days.

If space is limited and one wants to have a variety of different cultivars of tomatoes without having an enormous crop, then growing them as cordons might well be a useful method to try.