Florida Vegetable Transplant Growers News

Mark your calendars ... August 12 ... for a meeting in Immokalee. We have a number of things to discuss before the season gets into full swing. First item on the agenda is the "budless tomato syndrome". As fall approaches this syndrome will begin to raise it's ugly head, so let's plan our attack. Dr. Hazel Wetzstein (University of Georgia) will provide some electron micrographs that may shed a little light on the phenomenon. SWFREC budless research and an exchange of attitudes and opinions on budlessness will be topics of discussion.

Additionally, Mireia Arenas (Horticultural Sciences, graduate student), will discuss her work on coconut coir media; we'll see a video on current technology in seeders and irrigation; I'll give a research update on my program, and much more. Verlite has agreed to sponsor lunch for us as well. So, mark that calendar now ... August 12, 10 a.m. at the SWFREC in Immokalee.

Recent trends in vegetable transplant tray design have been toward more cells per tray. More cells per tray means more plants per house and more plants per house means greater production efficiency. But it generally means a smaller cell volume per plant as well. We have all heard a "root bound" plant is more problematic than an actively growing plant. So why would we want to produce plants in smaller and smaller cells?

We posed this question last fall in a study on fresh market tomatoes. We chose trays with 200 cells at 26 cc or about 1 ounce per cell, 38 cc cells (150), and 46 cc cells (72) and grew the seedlings for 5 weeks. At field planting, plants grown in the larger cells were considerably larger than those grown in the smaller cells in almost every respect. This growth difference continued for about 45 days in the field at which point plants from the smaller cell sizes appeared to catch up.

The trial was designed to let fruit color develop as a measure of maturity. At first harvest, 62% of the fruit from the 46 cc cells had attained some level of color compared to 55% from the 38 cc cells and 52% from the 26 cc cells. This advanced maturity was evident in all size grades (medium, large, extra-large). Overall yield (2 harvests) showed no difference due to cell size in the weight of fruit produced. However, the 46 cc cells produced a few more large fruit than the other cell sizes, which may again reflect advanced maturity. Earliness is an advantage when trying to hit a market window.

Our data may not be very dramatic, but it adds to the information on the benefits of larger cell size noted around the country in numerous crops over the past 30 years. Table 1 lists nine notable studies where researchers compared growing transplants in cells of varying volume. In 6 of the 9 studies, transplants grown in bigger cells lead to significantly increased early and/or total Yield. The trend toward higher yield with larger cells was also noticed in the trials that did not show statistically based differences. All trials exhibited larger transplants at planting when larger cells were used.

Why is bigger, better? Researchers have suggested a general reduction in stress, greater availability of water and fertilizer, unrestricted root growth, and greater shoot development as possible answers. Also more rapid field growth of the plants from larger cells aids in their ability to combat and resist insects, diseases, and other mechanical or physical stresses.

Larger cell sizes may add from $10 to $40 (depending on size) to your cost per thousand, and this becomes costly for crops like pepper where the planting density is high. However, in crops such as tomato or watermelon, the increase in yield and earliness could cover that small investment up front. Small growers, who may grow their own, would be advised to produce transplants in large cells simply for the competitive advantage.

So why not try a few trays of a considerably larger cell size than you are now using in a side by side comparison on your farm. We think you will agree that this is one case where bigger is better!

Table 1. A summary of 30 years of research on containerized vegetable transplant cell volume.*
Crop	State	Cell Volume (CMI)	Transplant Height (inches)	Field Yield (tons/acre)
Tomato	KY	2, 3, 4 inch pots	7,8, 12	1, 1.4, 1.8 lbs early fruit/plant
Broccoli	MN	04, 15,31	1.1, 1.6, 1.9	5.3, 5.8, 6.7 total
Tomato	MI	04, 19,39	3.9, 7.9, 8.3	3.6, 4.0, 8.0 early
Cabbage	MO	08,28,39	3.9, 3.5, 4.7	1.9, 2.1, 2.2 lbs/head
Pepper	KY	06, 19,39	7.5, 7.9, 8.7	0.7, 1.0, 1.9 early
Watermelon	GA	19,39	-	23.6, 25.4 total
Pepper	Israel	05,35,65	4.7, 6.3, 6.7	28, 27, 28 total
Watermelon	FL	19,31,66	-	22, 22, 23 total
Muskmelon	IN	07,36,70	25, 51, 69 leaf area in CM2	7, 12, 15 total

*Contact the author for specifics on any or all the studies listed. Not all data is represented in each study (Cm³,) 7, 8, ease of table format and presentation.