Small growers would benefit from growing seedlings

One of the ways in which small, diversified vegetable farmers can be at a competitive disadvantage is when it comes to sourcing transplants.

The larger greenhouse transplant suppliers are geared up to supply large growing operations, and it shows in their pricing structure.

"The cost for seedlings from a commercial greenhouse may be 5 to 10 cents for a large volume, but it can go up to 50 cents or more for smaller orders. Can you justify that for a head of lettuce? Probably not," said Christof Bernau, University of California, Santa Cruz, Center for Agroecology & Sustainable Food Systems farm garden manager. "A minimum order for some of the commercial greenhouses is 10,000 plants of one variety. For a lot of small diversified farmers, that may be too much."

Bernau is part of a team at the agroecology center that is researching the most efficient way for smaller farmers to germinate their own seedlings and teaching a class on the basics of greenhouse production.

The California Department of Food and Agriculture supported the demonstrations and training with a three-year, $265,000 grant to fund infrastructure improvements, classes, field days and a how-to publication for growers.

"The most common mistake new seedling producers make is either over- or underwatering; typically it is overwatering," Bernau said. "If damping-off diseases are involved, you will have either no germination or healthy seedlings will suddenly fall over. You need to take corrective measures."

One effective tool to control damping-off diseases is to manage the microclimate to discourage the pathogens.

"You can enforce a wet to dry swing to manage the pathogens, and you also need to promote good air circulation," Bernau said. "You also need a good temperature swing to push it higher or lower than the 60s or 70s, to make the damping off pathogens uncomfortable."

Another seedling disease-management technique is to dry peat moss on the soil surface to dry it out.

"We also blend something called Root Shield into our mix; it's a beneficial Trichoderma fungus," Bernau said.

As part of the three-year CDFA grant, the center is conducting trials on different soil media to germinate the seedlings.

Researchers are looking at a basic soil mix with and without compost, with and without blood meal, and with and without an application of fish emulsion fertilizer after germination.

"Most people producing their own seedlings would like to have a single recipe," Bernau said. But he confessed, "Our data shows it varies with the crop. We are still looking for the best mix for most crops."

A current trial is looking at the best results using commercially available media straight out of the bag.

As part of the evaluation, center staff member Skye McIntyre carefully removes a selection of seedlings germinated in the different media, shakes the dirt off the roots and then weighs both the shoots and the roots.

"So far, the lighter textured peat moss without amendments gives you the fastest germination, but the amended ones produced the best growth long-term," Bernau said. "One thing that has been confounding is that the second time we ran the trial, the compost alone seemed to be detrimental, but compost and blood meal seemed to help. Light mixes with no compost germinate faster, but with the compost they catch up and pass them."

There are areas of seedling production that he said even small farmers would do well to invest in labor-saving tools for different areas of seedling production.

"A vacuum seeder is infinitely faster than if you do it by hand," Bernau said. "It costs $2,500 for the model we have, but there are models for under $1,000 and there are a lot of do-it-yourself ones you can put together for less."

This tool holds one seed in place for each transplant cell until the vacuum is turned off and the seeds drop neatly into place.

"Your return on the investment could be very fast," Bernau said. "Once your flats are ready, we're looking at a minute to a minute-and-a-half to sew 242 cells in a tray."

Water management is another area where it is possible to improve labor efficiency and save money.

"Another efficiency is if you can automate your irrigation," he said, looking over the sprinklers that irrigate tables of seedlings in one of the center's greenhouses.

Some crops are more amenable than others to do-it-yourself seedling production, and Bernau advises a willingness to buy starters of the most difficult varieties from the professionals.

Lettuces, all the Brassica, and chard are among the easier crops to start, according to Bernau, as they germinate fast and consistently, and quickly grow to a size suitable for transplanting.

The harder varieties would include peppers, which take eight weeks or longer from seed to transplant.

"Lisianthus is very hard," Bernau said. "Maybe you can justify 50 cents a seedling for a specialty flower like lisianthus that's hard to germinate."

While the research continues, agroecology center staff has already shared the basics of growing transplants with a fair number of small farmers.

"We're training 36 to 39 people a year in the fundamentals of greenhouse and seedling production," Bernau said. "We will also be having field days in October and next February."

A free online and printed Organic and Sustainable Seedling Grower Guide booklet will be available next spring.

(Bob Johnson is a reporter in Sacramento. He may be contacted at bjohn11135@gmail.com.)