Growing Lettuce

Latest Update 9th July 2016.

Lettuce
  • Red Iceberg Lettuce are fast growing and compact.  They have a crisp texture and taste great.  
  • I have found them easy to grow all year round in our climate, although they need protection from the sun to stop them bolting in summer.
  • They benefit from the protection of pest exclusion netting in the warmer months.
  • I use a mulch of clean straw to protect the lettuce leaves from bottom rot, which is usually caused by direct contact with moist soil.
  • Like most organically grown vegetables, lettuce is rich in vitamins, minerals and a great source of dietary fibre.
  • Its pretty fast growing and I use it as a catch crop growing it in any available space in any bed.
  • We always eat it fresh from the garden on salads, in sandwiches and in wraps.
Details.
  • Binomial Name:                                        Lactuca sativa.
  • Family:                                                    Asteraceae.
  • Variety:                                                    Red Iceberg.
  • Crop rotation group:                                  Legumes.
  • Garden bed type:                                      Garden Ecobed.
  • Recommended soil pH:                             6.0 - 7.0.
  • Minimum sun per day:                              4 hours.
  • Plant spacings (centres x rows):                300 x 300 mm.
  • Weeks to harvest:                                     8 - 12 weeks.
  • Good companions:                                   Carrot. onion. beetroot. cabbage. marigold.
  • Climate:                                                   Warm temperate. 
  • Geography:                                              Southern hemisphere.
Nutrition. 
  • This food is low in sodium, and very low in saturated fat and cholesterol. 
  • It is a good source of thiamin, vitamin B6, iron and potassium, and a very good source of dietary fibre, vitamin A, vitamin C, vitamin K, folate and manganese.
  • More from nutrition data.self.com.
Growing Conditions:
  • They grow best in full sun in cooler months, but will grow well if shaded in the warmer months.
  • They need well structured rich organic soil.
  • The soil must be kept moist at all times. 
Soil Preparation. 
  • Clear space for Lettuce in February.  Add a 60mm layer of home made compost and cover with 50mm of straw mulch.
  • Leave the bed for 4 weeks to build up worm and microbial activity.
Growing Instructions.
  • Sow Lettuce seeds sparsely (10-12 only) in January on the surface of an organic seed growing mix in a mini pot, and lightly cover with finely sieved growing mix.
  • Soak the mini pot for an hour in a tray containing 10mm of water (preferably rainwater).  The water will wick up into the soil without flooding it. 
  • Sink the mini pots up to their rims in a Propagator.  This will keep the mini pot's soil moist until the seedlings are ready to transplant.
  • After 4 weeks transplant the 5 strongest seedlings individually into jiffy pots filled with organic potting mix and return them to the Eco Propagator.
  • Take the pots out of the propagator when the seedlings are ready to transplant, and move the mulch to one side in the prepared bed.  Plant the jiffy pots 300mm apart and water the seedlings in well.
  • Return the mulch as soon as the lettuce is established.  Push the straw under the leaves of the lettuces to help protect them against lettuce bottom rot.
  • I grow lettuce wherever there is available space (its a perfect plant to fill vacant spaces), but most of the time I can find a full row to grow them in.
  • They are usually grown with brassicas, which need similar protection against strong sunlight in the summer.  They are protected with light shadecloth right through the warmer months and heavy shadecloth is added in hot, dry, windy weather.
  • Apply a foliar spray of aerated compost tea every 4 weeks at the same time as all the other edible plants.
Repeated sowing.
    • Repeated sowings can be made every month, and when ready the seedlings can be planted in gaps left by crops recently harvested.  Make sure the soil in these gap has been properly prepared.
    Harvesting and Storage.
    • Lettuce can be harvested all year. 
    • Cut the heads off the Lettuce at ground level and allow the roots to decompose in the soil.
    • Lettuce does not store well and should be eaten within a few days of its harvest.
    Organic Pest Control.
    • Slugs and snails.  
      • Lettuce needs protection against slugs and snails, so use self adhesive copper tape around the base of the Ecobed to keep them out.
    • Cabbage white butterfly caterpillars.  
      • Repeated foliar sprays of aerated compost tea will deter caterpillars, but exclusion netting is the best defence.  
      • If they do get established spray the whole plant with Bacillus thuringiensis.  This natural soil borne bacterium is ingested by the caterpillars and they die within a couple of days.
    • Greenhouse whitefly.  
      • Aerated compost tea foliar spray toughens foliage against whitefly damage. 
      • Control any serious infestations by spray your crop thoroughly with organic horticultural oil (Eco-oil in Australia) as early in their life cycle as possible.
      • Spray again in a few days to ensure second generation whitefly do not survive.
      • Note Eco-oil smothers insects by blocking their breathing holes.  It is not selective and will kill beneficial insects if care is not taken, so spray early in the morning and target the whitefly as exclusively as possibl
    • Aphids (greenfly). 
      • Aphids can usually be dislodged using a jet of water, but if persistent, spray with Eco-oil.
    • Lettuce bottom rot.   
      • This soil borne fungal pathogen must be controlled using preventive measures.  Crop rotation is the best cure giving the soil time to recover from any infestation.  
      • Maintaining high worm and microbe activity in the soil with plenty of organic material, creates unfavourable conditions for Rhizoctonia solani the main fungal plant pathogen in lettuce bottom rot.   
      • Fresh straw or sand can be used as a barrier between the Lettuce leaves and the soil to avoid Lettuce bottom rot infecting the leaves.  
      • It is also thought that a Mycorrhizal fungi dusting of seedling roots will help protect the lettuce against bottom rot.