Pollinator Paradise      Leafcutting bees & alfalfa    The Solitary Bee Web   
  Binderboard
   New Mexico Native Bee Pollinator Project   Nampa Farmer's Market  About Dr. Strickler

A Pollination Moment
from Pollinator Paradise Farmer's Market E-mail reminders

5/10/2003
What's in Lettuce?

Lettuce is in the composite family, and therefore is a relative of daisies, chrysanthemums, and thistles.  If you let them bolt in the heat, they will send up a shoot with small yellow flowers on top, like the horrible wild lettuce that is a weed in agricultural fields. 

But we don't usually allow lettuce to flower unless we are producing lettuce seed.  Once they flower, lettuce stops making large leaves, and becomes bitter from alkaloids in the milky juice that they produce when they start to flower.  We grow lettuce in cool weather to discourage bloom.

Commercial lettuces have been bred to produce large leaves in a variety of colors and patterns.  Some form heads and some don't.  There are 4 main types of lettuce:  Romaine or Cos lettuces, loose leaf lettuces, Butterhead lettuces, and Iceberg lettuces.  The last two types form cabbage-like heads.  Of course, iceberg is the most common lettuce in restaurants and stores.

There was an interesting item on public radio's "Living on Earth" program last Sunday (May 4).  It was a report about recent studies that have found the rocket fuel, perchlorate, contaminating lettuce and other food crops.  At risk are plants that have been watered by the Colorado River in Arizona and California.  Most of the lettuce in grocery stores is from those states. 

According to the story, perchlorate can interfere with the normal production of thyroid hormones in developing organisms.  Babies, who rely on the hormonal system to trigger development, particularly brain development, might not have a sufficient supply of thyroid to develop properly if exposed to too much perchlorate.

Hmmm.  I wonder how many babies eat lettuce? Or would they be exposed to perchlorate in mother's milk if their mothers ate lettuce?

If you are interested, you can find the article at: http://www.livingonearth.org.  Search the archives for an item titled "leafy toxins".  The issue is apparently controversial.

Well, I don't know if that news will encourage anyone to buy lettuce at the local Farmers' Market, where our irrigation water is (hopefully) not contaminated with perchlorate or anything else. 

But here is something that you will find in lettuce and other greens:  Vitamin A.  According to USDA figures on the composition of foods  (http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl ), all lettuces are 94 - 96% water, and they contain 12 - 18 calories per 100 grams.  But compare Vitamin A in different kinds of lettuces, measured in IUs in 100 grams of each:

Iceberg      

330

Romaine     

2600

Butterhead   

970

Looseleaf   

1900 

 Pretty strong argument for the specialty lettuces, don't you think?  Our salad mix is full of them.

 Back to Pollination Moments

Top of Page     Leafcutting bees & alfalfa    The Solitary Bee Web   
Binderboard
   New Mexico Native Bee Pollinator Project  Nampa Farmer's Market   About Dr. Strickler

September 14, 2002
Copyright 2002, Karen Strickler. All rights reserved.