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?

7 thoughts on “Slimy Jungle – A Seed Lettuce Tale of Sorrow and Woe

  1. I live in north central NYS near Lake Ontario. We had an extremely wet/cold spring and now a very hot/humid summer. My lettuce has been stellar. I plant black seeded simpson, red oak, romaine, green head and mesculin varieties and all have produced well as has the arugula. I have noticed the head lettuce does tend to curl away from cneter rather than forming a large head but it has been crisp and sweet.

  2. Wow, I can relate to your slimy lettuce woes. I have the same problem here in Western Montana, not even trying to grow seed, just iceberg lettuce. I’ve been wondering if drip tape would be better irrigation for lettuce than sprinklers. How do you water ?
    Thanks for all the plant news all the time !!!
    – Jean in Mt

    1. Hi Jean,
      We irrigate head lettuce with sprinklers. We rarely see disease problems during dry periods even if we use sprinklers. However we only grow varieties that we know grow well in our conditions since we aim to harvest 300+ lettuce heads every week for market and our CSA basket program. Iceberg lettuces have unfortunately not made our reliable lettuce list or commercial harvest.

      If we mainly had dry weather, drip tape might be a solution for iceberg lettuce. But it is not uncommon for us to have weeks of rain at a time.

      Good luck,

  3. Now that’s good common sense, if other lettuces are doing fine (crispheads, leaf, romaine) maybe its the type of lettuce. Thanks for the fresh thought. We have cool nights here, 40’s generally, a late Spring and rainy summer this year. Nevada, Anuenue, Troutback, Buttercrunch bibb, Little loma, Blushed Icy Oak and De morges braun all did well here. Plus some volunteer red oak, that came with the carrot seed. Thanks for sharing : )
    Thanks for sharing when you have such a lot to do.

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