Lettuce season extension for warmer climates

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2024: $8,225.00
Projected End Date: 03/31/2026
Grant Recipient: Snow's Bend Farm
Region: Southern
State: Alabama
Principal Investigator:
Margaret Ann Snow
Snow's Bend Farm


No commodities identified


No practices identified

Proposal summary:

I am interested in exploring the possibility of extending certain
cool season crops into summer by utilizing shade cloths and
selecting for heat-tolerant varieties. The study I am proposing
would combine both of these specifically in regard to head
lettuce. There are more variables to be explored in the future,
such as overhead watering and misting systems, different types of
mulching, and other crops and varieties (kales and cilantro).
While researching squash bugs on our farm, an entomologist and my
partner noticed that the squash underneath the Proteknet was
growing at a much faster rate than the squash outside of the
netting. This could be due to it aiding in respiration and
cycling of CO2. If the lettuce grows more quickly under the
netting, it could then produce a marketable head more quickly,
avoiding some of the adverse effects of warmer temperatures. As a
farmer of twenty years myself, I would calculate costs and
consider the lowest cost and still most effective means of
achieving the results I aspire towards.

Project objectives from proposal:

In order to learn whether shade cloth can extend the season for
lettuce growth from late-June through mid-September in Alabama, a
50-foot bed will be planted every two weeks and covered with a
50% shade cloth. The cloth will hover above the crops, resting on
hoops set out every 5 feet. Another 50-foot section of each bed
will be planted at the same time but instead have the hoops and
Proteknet covering it. A 5-foot space in between the two will be
planted, but left uncovered as a control. Because we know from
experience that lettuce will not grow well in the southern summer
heat without some form of aid, any more than a small control
space would be a waste of resources. Beds would be planted at
two-week intervals from June 1st through July 15th and then
repeated on three other beds beginning August 1st. Three
heat-tolerant varieties of lettuce will be trialed; ‘Bergam’s
Green’ (green leaf), ‘Cherokee’ (red summer crisp), and
‘Lovelock’ (multicolored). 2- 128 plug flats will be seeded every
two weeks beginning on May 1st. Each flat will have equal number
of the three varietals. One month after seeding, one flat will be
transplanted and covered with shade, while the other is
transplanted and covered with Proteknet. Succession planting will
continue every two weeks for 12 weeks, creating 6 successions, as
the temperatures increase. In order to increase chances of
success, all transplants will be planted into pre-irrigated soil
in three rows with plants 12 inches apart within the rows. The
beds will be covered with white plastic mulch in order to lessen
weed pressure. Measurements will be taken weekly. The
measurements taken will be of the temperature both beneath each
shade cloth and beneath each insect barrier, as well as
temperature with no cover. Plant growth will also be measured and
charted weekly. Observations of physical characteristics such as
yellowing of leaves, tip burn, and tendency to bolt will be noted
weekly as well. When lettuces are ready to harvest, they will be
both counted (heads) and weighed. Marketable, as well as notably
unmarketable, data will be collected.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.