Trials were initiated to determine if cilantro and garlic chives could be grown in typical greenhouse bedding plant/vegetable transplant trays. Cell size and plant density were varied to determine the yield of the plants in a greenhouse situation.
Subirrigation techniques, capillary mat or "float" system, were used for both plants in this study. Capillary mat subirrigation utilized a constant water table system to maintain uniform water availablility in the cells (Buxton 1994). The "float" system utilized polystyrene trays that are placed (floated) on the surface of water, 15 cm deep, held inside a wooden frame with a plastic liner.
Garlic chives and cilantro were transplanted and grown from Oct. 1993 to May 1994 in polystyrene and polypropylene trays (Table 1). Individual experimental units were 0.1 square meter. Garlic chives and cilantro were grown in greenhouses with ambient light levels and set points of 17°C night temperature and 23°C day temperature. Plants were fertilized with water soluble fertilizer, 20-4-16, at levels of 50-70 ppm N. Fresh weights of the foliage and plant number were noted at the completion of the experiments.
Differences in the harvested fresh weight on a square meter basis were apparent in these experiments but this was due to changes in plant numbers and variable initial plant densities in the experiments (Table 2). There were no differences in harvested fresh weight of chive foliage with increased levels (80 ppm N compared to 40 ppm N) of fertilizer. Garlic chives grown for six and eight months had increased yields in fresh weight and plant numbers compared to those grown for two months (Table 2). Per plant fresh weight in the six-month-old plants was not larger than the two-month-old plants due to plant damage from thrips. Thrips can be a significant problem on garlic chives in the greenhouse. No pesticides are cleared for thrips on fresh herbs in the greenhouse so thrips screening and excellent santitation must be used to manage these insects.
The effects of cell size and plant density on yield of cilantro were variable. Initial trials demonstrated that lower plant densities may increase the harvested fresh weight of cilantro foliage even though the means were not statistically different (Table 3). Subsequent experiments demonstrated no statistical differences in the mean fresh weight on per plant basis in each trial (Table 4).
Differences in the harvested fresh weight on a square meter basis were statistically similar in these experiments due to the variability within the treatments (Table 4). There were no differences in harvested fresh weight of cilantro foliage with increased levels of fertilizer (100 ppm N compared to 50 ppm N). The yield of cilantro foliage was increased in the experiment completed in the spring. This was probably due to increased light levels in the greenhouse in the spring where these plants received a total of 992 mol m-2 PAR during the crop while plants in the fall received 435 mol m-2 PAR.
Cell width x depth (cm) | Cell vol. (cm3) | Cell no. /m2 |
Polystyrene trays | ||
2.4 x 5.7 | 17 | 1044 |
2.8 x 7.6 | 23 | 861 |
3.8 x 11.5 | 61 | 549 |
5.1 x 7.6 | 75 | 310 |
7.6 x 7.6 | 160 | 138 |
Polypropylene trays | ||
2.1 x 2 cm | 6 | 1076 |
2.1 x 4 cm | 11 | 1076 |
Foliage fresh wt | |||||
Initial plants/m2 | Cell vol. (cm3) | No. plants/ cell | g/plant | g/m2 | Plant no. increase (%) |
Transplanted Oct. 7, harvested Dec. 15, 1993 | |||||
828 | 160 | 6 | 1.49 | 1741 | 145 |
930 | 75 | 3 | 1.47 | 1732 | 128 |
1098 | 61 | 2 | 1.49 | 2255 | 125 |
Transplanted Oct. 7, harvested Dec. 15, 1993 | |||||
1550 | 61 | 1.45 | 3757 | 171 | |
1550 | 75 | 1.30 | 2751 | 141 | |
1550 | 160 | 1.20 | 2399 | 129 | |
Transplanted Nov. 5, harvested Feb. and Apr. 5, 1994 | |||||
828 | 160 | 6 | 1.49 | 2867 | 233 |
930 | 75 | 3 | 1.47 | 2792 | 205 |
1098 | 61 | 2 | 1.49 | 3600 | 220 |
Transplanted Oct. 5, harvested Dec., 1993, Feb., Apr., and May 10, 1994 | |||||
138 | 160 | 1 | 2.72 | 1356 | 361 |
272 | 160 | 2 | 3.12 | 3056 | 360 |
549 | 61 | 1 | 2.88 | 5154 | 326 |
1098 | 61 | 2 | 2.84 | 8321 | 267 |
Fresh weight | |||
Plant no. /m2 | Cell vol. (cm3) | g/plant | g/m2 |
689 | 61 | 1.52 | 984.5 |
839 | 75 | 1.30 | 1090.0 |
968 | 23 | 1.40 | 1353.6 |
1076 | 17 | 1.36 | 1466.6 |
1377 | 61z | 1.35 | 1859.3 |
Foliage fresh wt. | |||
Cell vol. (cm3) | Plants/m2 | g/plant | g/m2 |
Seed sown Oct. 5, transplanted Oct. 15, harvested Nov. 15, 1993 | |||
61 | 1550 | 2.04 | 3155 |
75 | 1550 | 2.05 | 2926 |
160 | 1550 | 1.98 | 3065 |
Seed sown Sept. 27, transplanted Oct. 15, harvested Nov. 11, 1993 | |||
6 | 1550 | 1.66 | 2564 |
11 | 1550 | 1.61 | 2491 |
75 | 1550 | 1.51 | 2336 |
Seed sown Feb. 27, transplanted Mar. 15, harvested Apr. 12, 1994 | |||
61 | 775 | 4.44 | 3440 |
75 | 775 | 5.64 | 4373 |
160 | 775 | 4.67 | 3617 |
Assumptions for winter greenhouse crop of garlic chive foliage | |
1. | Perennial crop, harvest every 8 weeks from Oct. 1 to June 1. |
2. | Each crop requires 8 weeks and plants are grown at 1550 plants m-2 |
3. | Utilize 50 m2 of bench space for each crop. |
4. | Receive $.70 per 2 oz (30g) package. |
Gross returns calculations | |
2.5 kg foliage m-2 x 200 m-2 x 4 crops = 2,000 kg x 5% shrink = 1,900 kg | |
1,900 kg/30 g per 2 oz. package = 63,333 packages | |
63,333 packages x $0.70 = $44,333.00 | |
$44,333/200 m2 bench space = $222 m-2 gross returns for winter crop | |
Assumptions for winter greenhouse crop of cilantro foliage | |
1. | Thirteen crops, sow seed every 2 weeks from Oct. 1 to Apr. 1. Use greenhouse from Oct. 1 to June 1. |
2. | Each crop requires 8 weeks and plants are grown at 775 plants m-2 |
3. | Utilize 50 m2 of bench space for each crop. |
4. | Receive $.70 per 2 oz (30g) package. |
Gross returns calculations | |
3 kg foliage m-2 x 50-2 m x 13 crops = 1,950 kg x 5% shrink = 1,852,500 g | |
1,852.5 kg/30 g per 2 oz. package = 61,750 packages | |
61,750 packages x $0.70 = $43,225.00 | |
$43,225/200 m2 bench space = $216 m-2 gross returns for winter crop |