2.3. Soil properties and pot experiment set-up (pot trials 1 and 2)
Lettuce plants were grown in free-draining pots to prevent the
accumulation of
salts from the added nutrient solutions (see S1.2).
Two layers of gravel (large and small sized) were placed in the bot-
tom of each pot followed by 200 g (dry weight) of soil. A sandy
soil (from Mt. Compass, South Australia) was oven dried at 60 ◦ C (7
days), sieved
(