Category Archives: Diseases

Identifying Diseases & Pests

A lot of things try to chomp, munch, consume, and destroy our crops. Before you can figure out what to do, it’s good to know what the problem is!

My favorite reference on the subject is Diseases and Pests of Vegetable Crops in Canada, which is available as a print book. But it is also now available online for free! You can find it here.

Even though Canada is in the title, most of these diseases and pests do not respect the borders! This book is great for all veggie growers.

I hope your summers are going well, and that you don’t need this kind of book too much.


Book Review: Breeding Organic Vegetables

Almost 10 years ago, NOFA released a series of handbooks on organic principles and practices. These were compact affordable books written by experienced farmers that gave solid introductions to poultry production, seed saving, crop rotation and more. I devoured these books.

NOFA-NY recently published a book that follows in the previous handbook series’s steps: Breeding Organic Vegetables A Step-by-Step Guide For Growers by Rowen White and Bryan Connolly. (Available from NOFA-NY or download it here.)

This book brings crop improvement and breeding to the garden/farm.

The first 3 chapters are a cursory review of seed saving: the why, the history, and the basics. These chapters set the context for what follows.

Chapter 4: Step-by-Step Crop Improvement brings us into the heart of the matter. Rowen and Bryan present 9 easy-to-follow steps that will not only let you strengthen a plant’s tolerance to all kinds of stresses including “diseases, insect pests, weeds, drought, heat, cold and variable soils” but also breed for color, shape, size and taste!

These steps start logically with where you are and what crop you want to work with, then setting your project goals and making a plan to achieve these goals. Next, you carry out the plan and evaluate. Finally you repeat annually until your crop is improved.

Rowen and Bryan state that “achieving these objectives often takes many years, but in jut a year or two a grower can often see measurable improvements in seed stock and plants.”

Chapter 5: Grower Breeder Recipes for Better Vegetables demonstrates how five growers have improved their crops. These profiles illustrate what is possible from cold hardy beets and arugula to dwarf blue sweet corn.

The book ends with a number of appendices. Appendix F covers breeding approaches to different species in the major crop families.

Just under 100 pages, this book is a quick read. It is a simple yet thorough introduction to what can be a complex topic. Once you get through Breeding Organic Vegetables I doubt you’ll be able to resist running out to the garden and improving all sorts of crops.

Breeding Organic Vegetables A Step-by-Step Guide For Growers is available from NOFA-NY or you can download it here.

What Is Seed Quality?

Seed quality was one of the big topics at USC Canada’s Train the Seed Trainer sessions. All the participants had a lot to say on the topic. And though we had many conflicting opinions on other seed issues, we had consensus making a list of seed quality concerns.

I’ve taken that list and broken it into a few categories and elaborated on each of them:

  • Basic seed concerns
  • Physical handling concerns
  • Genetic concerns
  • Traceability concerns

Basic Seed Concerns

These are some of the first things that folks thing of in terms of good seed:

  • Germination rate: Does the seed germinate well?
  • Seedling vigor: Do the seedlings grow vigorously?
  • Seedborne diseases: Is the seed free of problematic diseases?

Physical Handling Concerns

  • Cleanliness: How much chaff, dirt, or dust is present?
  • Presence of weed seeds
  • Handling mistakes: Was the variety mislabeled? Was there an accidental mixing of another variety of the same species during cleaning or packing?

Genetic Concerns

  • Varietal purity: Has the variety cross-pollinated?
  • Population size: Was seed saved from a large enough population to maintain a wide genetic breadth?

Traceability Concerns

Where is the variety strain from originally? Is it simply another variety that’s been renamed? How were previous generations handled? Does the variety perform/appear different from what it once did?

What Is Seed Quality?

You might notice that I have highlighted all of the above as concerns. In the end we did not put forward a list that defines quality seed as each of these concerns is not all or nothing. They depend greatly on the end use of the seed.

Beets with a 55% germination are fine for a home garden though none of us would want to sell those beets seeds. Slightly crossed up tomato seed is probably good for the vegetable grower who saved it though again none of us would want to sell the seed.

Generally speaking if the seed is for sale, then high standards need to be met, but seed saved for personal garden and farm use needs to meet the standards the seed saver can tolerate.

Do you think we’ve missed anything in this seed quality discussion?

What are your seed quality concerns?

One comment one seed growers made was that he doesn’t often hear back from his clients after they’ve ordered seeds until their next seed order. He  would love to hear their complaints about the seeds (if they have any.) And of course he loves to hear from thrilled clients too!

So, go  and write your seed sources a letter to tell them what you don’t like so much and what you love!

My trip to the OSA Organic Seed Growers Conference

On Jan 19-21, 2012, I attended the 6th Organic Seed Growers Conference in organized by the Organic Seed Alliance (OSA). The event started off with a one-day tour of the Skagit Vally seed region and then two days of conferences in Port Towsnend, WA.

If you missed the event, you can download the conference proceedings or view videos of the plant breeding sessions through eOrganic.

Though I did participate in a panel on marketing and growing seed profitably with Maud Powell and Steve Peters, today I won’t be posting about that but about the rest of my experience.

Pre-Conference Skagit Valley Seed Tour

Skagit county produces approximately 8% of the world’s spinach seed, 25% of the world’s cabbage seed, and 50% of the world’s beet seed (from WSU Skagit County Agricultural Statistics 2010) .

Here are some of the highlights of the tour:

Field Tour

A couple of days earlier about a foot of snow had fallen (an exceptionally large volume for this area). The walking part of the tour was subsequently canceled and all the following field pictures were taken through the tour bus window.

Here is a field of overwintered cabbages for hybrid seed production. The tour guide mentioned there were 2 rows of female plants for one row of male plants.

Another shot of a cabbage field. There is a v-ditch every 12 rows for drainage.

This area also produces a lot of raspberries.

Pinning Maps

With so many seed crops grown in one area, isolation distances are a big concern. Seed companies growing seed in the valley meet every year to decide who will grow what crops where using pinning maps.

In the Skagit Valley seed companies meet at WSU Mount Vernon Research Center for this process.

These are the cabbage pinning maps.

This is a chart of minimum isolation distance for different types of Brassica oleracea.

The red lines indicate areas where only one type of Brassica oleracea may be grown.

The pinning order is determined randomly. The first person pins a field for their crop. Then the next person pins a field. Each subsequent person needs to respect the minimum isolation distance from the fields that are already pinned.

This way seed companies cooperate to make sure their seed crops maintain varietal purity.

Soil Testing For Spinach Seed Crops

Spinach seed crops are particularly sensitive to bacterial and fungal disease. A 10- year crop rotation is the minimum to break many of these spinach disease cycles. In some cases this isn’t enough. Prior to pinning, growers can bring soil samples to WSU Mount Vernon Research Center to determine whether their soil is indeed disease-free.

Spinach seeds are planted (with replication) in the soil in a greenhouse in January. Within a month it is possible to evaluate the spinach seedlings to see what degree of disease might be expected.

Dr. Lindsey du Toit runs the vegetable seed pathology program.

The Conference

When I came to the previous Organic Seed Growers Conference in 2008 in Salem, OR, I was bombarded with information about climate appropriate seeds, plant breeding, seed cleaning details,  dynamics of the vegetable seed industry, and more.

Having already had this experience, I wasn’t at the 2012 conference only for seed information. I was here to be inspired (and I was inspired – especially about seed libraries, which I’ll be posting more about soon) and to mingle with the seedy underbelly of the organic farming world. In addition to seeing many old friends, I made some new friends.

Some folks I’d been reading about, or following their blogs, or even ordering/growing their seeds. I got to meet Sarah Kleeger and Andrew Still of Adaptive Seeds (and the Seed Ambassadors Project)  – Sarah was a touch disappointed I didn’t have a French accent.

I was surprised to be talking with Madeline McKeever of Brown Envelope Seeds. She was a long way from Ireland. She told me this wasn’t the first OSA conference she’d gone to either.

With other folks this was the first time I touched base. I spoke with Holli Cederholm of Proud Peasant Farm (who also works for Fedco) about how crop planning books don’t seem to factor in the food that the farmers eat. I was impressed by how much food Holli puts up and I thought Fred and I need to add a homesteading chapter if ever we revise our Crop Planning book.

I chatted with Doug Baty of Wild Plum Farm for quite a while about garlic. He couldn’t believe how big our porcelain garlic grew. I couldn’t believe how big his artichoke garlic were.

Sometimes you have to go a long way to meet someone from close to home. Though she’s now based in California, Rowen White of the Sierra Seeds Coop  grew up a couple of hours from Montreal. She is also the author of the just-published Breeding Organic Vegetables (available through NOFA NY).

I kept running into Chris Hardy of the Village Farm in Ashland, OR. We talked a lot about Tulsi.

And I got to know some folks better that I’d only met briefly at the 2008 conference such as Hanako Myers and Marko Colby of Midori Farm. I think every farmers market needs quality locally-produced kimchi and sauerkraut.

I did meet a lot of other folks too, including a number of people who’ve been reading Going to Seed. It was great meeting and talking with everybody. Seedy people are an interesting and friendly lot.

If you haven’t been to a OSA conference, you should. The next one will probably  be in 2014. I’ll likely be there.

(P.S.  the just posted Five Books Dan Brisebois thinks new farmers should read)

Slimy Jungle – A Seed Lettuce Tale of Sorrow and Woe

The following story took place last summer.

These are some red iceberg lettuces I was growing for seed. Everything looked great.

The rows in the front have had their outer leaves removed to increase ventilation. The rows in the back still have their outer leaves.

Do you see the holes in the lettuce patch? Over the next couple weeks, as the lettuces started to bolt, the red icebergs also started to rot. Whole heads would go from perfect salad material to slimy to gone in a couple of days.

For a brief period it was a real slimy jungle.

By the end of July, only a handful of plants survived and then they too succumbed to slime. A less than glorious seed crop.

What went wrong?

The simple answer is that this variety is not very disease tolerant. Here are some other thoughts.

Iceberg and other tight headed lettuces can be a challenge in humid climates like ours. The tightly wrapped leaves  of these lettuce types hold moisture and create an ideal habitat for bacterial and fungal diseases.

I had thought last year would be ideal for lettuce seeds as it had one of the driest summers in a long time. Still in our climate, even the driest summers have a lot of humidity in the air.

Another option is poor crop rotation. In 2009, there had been chicories and lettuces right beside where the 2010 red iceberg plot would be. Though the 2009 lettuce crop had been a success there had been some traces of disease. Any lettuce pathogens would have built up over the 2009 season and been present in higher numbers for the 2010 season.

The combination of high disease pressure and tight iceberg heads might have been the losing combination.


How is this year’s lettuce seed crop? Well, for on thing I’m not growing any red iceberg lettuce for seed. I prefer seed crops that yield seed.

I’ll post some pictures of this year’s bolting lettuce soon.

How do your lettuce seed crops fare in your climate?

Radishes Blooming and Pruning Lettuce

Last week, I received a few e-mails about growing radish seed. Here are a few radishy answers for those questions. Also, I have been pruning lettuce leaves to increase ventilation.

Radish Seed

These radishes have begun to bloom. These are grown 2 rows/bed with 18″ in-row spacing. They seem to be smaller plants than some other radishes I’ve grown out. They might still bulk up, but I wonder if I could have planted them tighter.

I grow spring radishes (as opposed to winter storage radishes) as annuals:

  • We seed them densely and harvest a few weeks later.
  • Emily (Tourne-Sol radish buncher extraordinaire) selects those she likes by their for roots, stems and so forth. The rest go to market.
  • I haven’t tried this but Greta has told me to then put the roots in a bucket full of water and discard the floaters (too pithy!).
  • I top the chosen radishes and stash them in the fridge for 7-10 days. This simulates overwintering and gets the radishes to bolt at the same time.
  • I then transplant the radish stecklings (roots) to the field.

To successfully grow radishes as annuals for seed, I have discovered they need to be started as early as possible.  I found that when I seeded in early that after fridge time and stecklings getting established in the ground, the radishes only bolt in late July – doesn’t leave much time for plants to flower and set seed before fall rain.

This year we seeded radishes in a tunnel  in late March to get an additional month of seed growing potential.

You can read more about radishes in Principles and Practices  of Organic Radish Seed Production from  the Organic Seed Alliance. (Dowload the document free from their website.)

Pruning Lettuce

The lettuce plants I transplanted at the beginning of April are turning into leafy monsters. I went in on Monday and took off the outer leaves to let the air in. My continuous fear with lettuce is that it suddenly turns to jelly.

Red Iceberg lettuce. The two first rows have been cleaned up. Compare with the lettuce jungle in the back rows.

As I do this, I rogue out any slimy specimens.

I try to handle lettuce on a sunny windy day so the exposed plant stems can dry and heal before submitted to more damp overcast weather.

All this pruning creates a lot of leafy biomass.

Luckily, I have a few helpers who love to process such tender biomass.


Irrigating with Sprinklers and Drip Tape

It’s been dry. With less than an inch of rain in weeks and weeks, and record high temperatures, our plants look wilted. Whereas we systematically irrigate germinating vegetable crops and leafy greens,  I usually rely on the not so uncommon spring rains for our seed crops to get established. However, this year as I was weeding some mizuna seed plants, I pulled a couple to  rogue out some underperformers.

The mizuna roots had barely extended from the bone dry root ball. My heart broke a little for these guys. We quickly added the seed gardens to the irrigation list.

Our irrigation regime is designed around both overhead sprinklers and drip tape.


We water most vegetables with sprinklers. I love sprinklers since they don’t interfere with regular weeding and they are easy to move.

The sprinklers are connected with a simple pressure fit plug. (This convenient plastic junction is also the weakest part of our system. After 4 years of use, we had to start replacing broken inserts.)

To move the line, two people stretch the pipe over 6 beds to the next irrigation spot. We plan our plantings to reduce the number of sprinkler moves.


I decided to use drip tape for the emergency seed crop irrigation, as the sprinkler lines were tied up elsewhere. Also, if this turns out to be the summer where it doesn’t rain, we might need to keep watering these crop when they go to flower and  start to set seed.

We use drip tape on tomatoes, peppers, eggplants, cucurbits and flowering plants. These guys all have  fungal and bacterial diseases that spread when their leaves (and flowers or seeds) are wet.


Since we rotate crops with different irrigation needs through the field, we designed our irrigation system to accommodate  sprinklers or drip tape everywhere.

We have regularly spaced valves with cam locks on our irrigation main lines.

We can attach a sprinkler line to a valve.

Or, we can install a drip tape header on a valve.

This flexibility reduces headaches. When the weather gets extreme, we have enough headaches as it is. If only irrigation were as easy as hanging a fresh load of laundry to challenge the rain gods!