Wednesday, July 16, 2014


On-Going Seed Projects in San Mateo County

Steve Peters, head of Seed rEvolution Now, is a research agronomist, organic farmer, and organic seed expert. Upon returning to California after an absence of over 35 years, he has been working to form connections with farmers to weave a seed network for Northern California, centered on the San Francisco Bay Area. Working with collaborators within a 100 mile radius of San Francisco, he always tries to be flexible and responsive to individual situations and needs. Here are just a few of his current projects close to home.

Considering that isolation is a key factor in avoiding contamination by unwanted pollen for certain crops, Tunitas Creek Ranch is a perfect place to do seed work. It lies hidden, well off a little-used road, and up a deep narrow valley. It's just the right distance in from the coast to be spared most of the fog. This lovely property has been carefully gardened for many years by our friend Aaron Dinwoodie.

Aaron is the son of a California farmer. He understands the value of seed adapted to his unusual site, and for quite a few seasons he has been saving seed from open pollinated crops that do well here. 

Here, for example is celeriac in bloom, promising abundant, fertile seed. It is  possible to save seeds from many types of crops in a fairly small amount of space. The key is in knowing and working with the reproductive strategy of each kind of plant.


Here is one of Aaron's beautiful vegetable gardens, where he does small-scale seed work as well as grows food. Seed saving can be done on a variety of scales, from backyard gardens to large fields requiring mechanized equipment.

In an on-going collaboration, Aaron and Steve are working together now on several trialing projects, including one for Steve's multi-headed broccoli selection, one for the tasty and nutritious Andean tuber, ulluco, and one for the remarkable Japanese angelica, ashitaba. This is just one of the many ways that Seed rEvolution Now is working to expand biodiversity, cooperation, and food sovereignty in the Bay Region.

These nice, fat, dense Nappa cabbages in Aaron's garden are a hybrid variety, which means they cannot be saved for seed. I show them as an example of the standard to which Steve is hoping to raise open-pollinated Nappa cabbage: to have dense, erect heads consistently throughout the population. There are very few OP Nappa-type Chinese cabbages available in the seed catalogs at this time. We are working to change that situation.

Down the coast a few miles lies lovely Fifth Crow Farm, where Steve has been working on several projects over the past two years, in a maritime climate that brassicas love.

This was made possible thanks to the generosity and vision of the three farmers who operate this productive organic farm: Teresa, Mike and John. Without their support, this work would not be accomplished.

They provided flats and potting soil, watered the seedlings, and donated row space and water in their fertile field. In return, Steve is working on seeds which should be of benefit to their operation, and has taught a seed saving course on the farm. This is the kind of collaboration we enjoy! Thanks, guys!

A year ago in the spring, Steve started over 700 seedlings each of two promising open-pollinated varieties: 'Early Green' broccoli and 'Nozaki Early' Nappa cabbage. Last year he grew these in a part of the farm which was infected with clubroot fungus. Any plants which showed susceptibility to the disease were removed. Thus, only those which displayed some resistance to the disease, as well as expressed good form, a dense, compact head, and were slow to bolt, were left to set seed. Seed was saved from each chosen plant individually. This spring each plant's progeny were set out in carefully labeled blocks, to further select for the best of the best.


Orange flags designate each "family" or progeny line. The goal is to reduce the population to only a few families, which will then cross pollinate to mingle and concentrate the best  genetics.

On arrival, Steve walks purposefully down the long row. doing a quick survey of how each "family" is expressing its unique genetic traits. At this point, he intends to remove any families which are below his exacting standards.

Plants are scoped out visually, and felt manually to judge the solidity of the head.

This head is beginning to go to seed, so it was pulled. Kimchee!

The culling is merciless. When trying to improve a variety, it is important to remove inferior plants before they can flower and pollinate the flowers of those you want to save. However, the culls can be eaten, sold, fed to livestock, or composted. No waste.

Broccoli goes through the same process. Needless to say, we've been eating a lot of Nappa cabbage and broccoli lately!

 A week later, the Chinese cabbage which was retained has almost all begun to bloom.

All, save this especially dense head. Apparently its leaves were so tight that the flowers were unable to emerge. It threatened to rot before it could flower. Steve really liked its quality, and decided to take drastic measures. He cut off the top of the head to open it up. We have seen that cauliflower does much better when two-thirds of the "curds" are removed before it bolts, giving the remaining flowering branches more room to emerge. Steve's hoping the same principle will apply here.
OK, now time to show your stuff!

 The broccoli Steve chose, Early Green, is a multi-headed type, with a 3-4" center head, filled by abundant side shoots. He has found that it makes no significant difference to the seed yield whether or not he harvests the center head, so we are happily eating those.

 Five heads bundled together. The nice thing is that the stems are quite tender and tasty, and the side shoot production goes on for a long time, making this an ideal crop for a backyard gardener or market grower seeking prolonged harvest and greater overall yield than single crown-cut hybrids provide. This winter we will be offering this seed for sale.

On another part of the farm, a row of beets is blooming. The Fifth Crow farmers were worried because their favorite beet variety had disappeared from the catalogs. This happens more and more often, as seed is maintained by corporations interested in maximizing their profit. Only the most popular, profitable varieties interest them. Fortunately, the farmers still had a few beets in their cold storage room. Steve was able to coach them on replanting the best roots this spring for an early fall seed harvest. If all goes well, there won't be any shortage of beet seed, now! In future years it will be wise to continue to select superior roots to improve the strain and adapt it to local conditions.

If you are a farmer, gardener, or community organizer who has interest in saving and selecting seed for organic cultivation, you can contact Steve Peters at Seed rEvolution Now. You may wish to become involved in our seed collaborative for the San Francisco Bay Region, or you may need Steve's help in learning how to get started. You can email Steve at: www.stevegrows@gmail.com



Wednesday, April 23, 2014

Broccoli and Napa Cabbage On-Farm Plant Breeding Projects at Fifth Crow Farm, in Pescadero, CA by Steve Peters


Open-pollinated, on-farm breeding offers important advantages to the farmer/breeder to adapt a crop to his or her unique environment. 


Fifth Crow Farm is a certified organic produce farm located near the Pacific coast in central California, a few miles from the picturesque town of Pescadero. The region is both blessed and challenged by the maritime climate. Summer and winter temperatures are moderate, and days are often foggy.

The good folks at Fifth Crow, Teresa Kurtuk, Mike Irving, and John Vars, were gracious enough to allow us to undertake a plant improvement project on their land. Over a delicious farm-fresh lunch, we discussed strategies for integrating the seed work with their on-going vegetable farming activities.



For this location, I chose to work with two OP brassicas; a Napa-type (heading) Chinese cabbage called Nozaki Early, and an heirloom broccoli called Early Green, favored for its high-yielding production of side shoots. In the commercial trade, both of these crops are dominated by F1 hybrid varieties, which means that farmers cannot save their own seed. We feel it is necessary to offer more choices of good quality open-pollinated varieties for seed sovereignty and food security.                        


My goal from the outset was to develop a vigorous and reliably-heading Napa cabbage, and a broccoli with tight, well-formed heads, and extended harvest.  Seedlings were placed in the field in early May. We planted about 750 transplants for each crop. 

The Napa cabbage seedlings were covered until mid-June, to protect them from flea beetles. The large populations provided me the opportunity to select only the very best plants (about 10% of the total) for seed production.




All selections were made prior to any flowering, to avoid pollination from culls. Chosen plants are flagged, and left to mature. This approach has the added benefit of allowing harvest for fresh produce of any plants not to be saved for seed.

With the Napa cabbage, I was selecting for sturdy, dense, upright heads of substantial size. The ideal form was  barrel shaped, however, I allowed for some variation in the size and shape, if a plant showed outstanding vigor.

 Culling began as soon as the floating row cover was removed, in mid-June. This plant was rogued-out, as it was a premature bolter. Rejects made great kimchee!

 Plants were also removed if they had loose heads, were stunted, or had other forms considered off-type. The maritime climate of this region provides an extra-long window of good brassica growing conditions. However, Napa cabbage, when sown in spring, has a tendency to form looser, more open heads because of increasing day length at this time.  Similarly, the florets of broccoli are also more open in spring plantings. The summer planting, with decreasing day length conditions, results in tighter, better-formed heads, and is generally considered the optimal planting time for these crops.

I chose to plant in spring deliberately, when days are lengthening, in order to observe plants in less than ideal conditions. This exaggerated the individual plant differences within the population, allowing for easier discrimination. Under perfect conditions, phenotypic variations could go unnoticed.

Within a few weeks we noticed a large number of sickly plants in both crops, particularly among the Napa cabbage.

On pulling these up, we discovered the problem: club root, or Plasmodiophora brassicae. It is caused by the invasion of a phytomyxea, a soil-borne plant parasite, into the roots, creating the obvious clubbed roots and hampering the plant's ability to uptake moisture and nutrients. More than one quarter of the population of both crops was removed due to this disease. These plants went into the landfill rather than the compost or to the chickens, to reduce the chance of spreading the infection.

While the entire field harbored this disease, certain areas were especially hard-hit, as can be seen by the gap in the middle of the plot above. At first this seemed like a disaster, but we quickly realized that, rather, it might be an opportunity to select for club root tolerance in our crops.

The broccoli was also affected by club root, though not as seriously as the Napa cabbage. 

The first Napa cabbage plants began flowering in late June, and by late July every remaining plant was flowering.

 Brassicas are insect pollinated, as might be guessed by the fairly showy and colorful flowers. Bees will travel up to a mile in search of nectar, so it is important to isolate seed crops from other flowering brassicas of the same species. Napa cabbage is Brassica rapa, the same species as turnips, and broccoli raab.

 This Early Green broccoli displayed good form and was left for seed. Broccoli is Brassica oleracea. This species also includes cauliflower, cabbage, kale (except Siberian kale), collards, Brussels sprouts, kohlrabi, and Chinese broccoli.

A great example of a big plant with many side shoots.

 I experimented with leaving the center head for seed on some plants, while harvesting it on others and allowing the side shoots to produce all the seed. There was not much difference in seed yield per plant between these approaches; therefore I recommend harvesting the center head for fresh produce...enjoy!

           Let the fun begin! All remaining plants (55 Napa cabbage; 72 broccoli) intermated promiscuously! No fear of cross-pollination between the two distinct species.

 The seed harvest window for the broccoli lasted for about 3 weeks - from late September to mid-October.  Whole plants, including roots, were pulled, then thoroughly dried in a sheltered, airy space.

Each plant was harvested and processed individually. Seed yields per plant ranged from 1-20 grams (2/3 oz) for Napa cabbage and 6-95 grams (over 3 oz) for broccoli.

The threshing step, i.e., removing the seed from its pod and stem, was accomplished by hand-rubbing. 

Seed from each plant was kept in its own labeled bag.

A small, round-holed screen allowed for all the seed (and a little chaff) to drop into the container below. 

Not quite clean...yet.

 The final cleaning step is to gently spill the seed in front of an electric fan. Before electricity, this winnowing was accomplished by tossing seed and chaff up in the wind. Lighter chaff is blown away, heavier, viable seed falls onto a tarp or container for collection.

With the cleaning process completed, the seed is put in individual bags. We have now begun year 2 of the project. Last year was the initial field selection. This year we will conduct the progeny testing. For both the Napa and the broccoli, we have planted 30 seeds from each of the 50 highest seed-yielding plants from last year. In a few weeks we will transplant out the most vigorous 15 plants from each of these, for a total population of 750 for each crop. In the coming year, I will evaluate each group of fifteen plants as a distinct "family". This is called progeny testing. As I discover superior families, I will eliminate the less desirable groups. I call this sheparding the good genes. More on this process in a future blog.