Lesson 7 – Part A: WHY DO PLANTS NEED WATERING?
Lesson 7 – Part B: HOW TO SAVE WATER IN YOUR GARDEN
Lesson 7 – Part C: MULCH YOUR GARDEN
PREPARATION FOR LESSON 7:
Please read through Lesson 7 text for students.
Most of this lesson can be demonstrated in the garden. Please ensure that a hose and watering cans are available before the lesson begins.
Use whatever organic mulch is available at the time of giving this lesson. If you choose to use drink bottles for watering tomato plants, etc., it is advisable that an adult remove the bases before the lesson. This is easily done with a Stanley knife or box cutter if you leave the lid of the bottle screwed on to provide some resistance for the first cut.
If you are presenting this lesson during winter in a cool climate, and mulching garden beds is not suitable for your particular situation (see Easy Organic Gardening and Moon Planting pp 171-2), you can defer Part C of this lesson to a more appropriate time.
This section is the only theory part of this lesson. It includes a simple explanation of transpiration -– the driving force for water movement through plants, and how water stress makes plants more susceptible to pests and diseases.
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This section includes basic practices for the efficient watering of gardens. You can read through the lesson with the class while in the garden and demonstrate how to check if plants need watering, and sensible use of garden hoses.
Please note: We recommend that you do flush some water through hoses that have been left attached to taps, as hoses are made from PVC plastic that can leach very toxic chemicals into water, especially in warm weather. It is not advisable to direct the contaminated water onto food gardens. Flushed water can be run onto a lawn or near non-food plants. If hoses are disconnected and moved to a cool place for storage after use, any remaining water will drain out and students will only have to check the nozzle setting before watering. You can find extra information on drought-proofing gardens in Easy Organic Gardening and Moon Planting pp 159-168.
WATER FOR WILDLIFE
If your students want to install a birdbath, explain to them that it should not be in, or very close to, garden beds as some birds like to eat food crops and ripening seeds, and some beds may need netting at certain times.
Approximately one third of our foods rely on bees for pollination, in some way. Bees will regularly visit gardens where they can find clean water. Try to include a lavender bush or two near your garden area. Bees love it, and it has a calming effect on both the bees and children.
Companion planting tip: The aromas produced by lavenders, rosemary and thyme also help to keep some garden pests away by masking the smell of other plants.
WATER SHORTAGE AND SALINE WATER 
If your school is in an area where you are only allowed to use garden hoses for a short period, you can build a 3-cm high wall of soil around every side of your garden beds, as this will enable you to water garden beds very quickly.
Mulch the entire bed, including the wall around the edges. When your plants need water, flood each bed with 2 cm of water. Remember to water under the mulch. Rimmed beds are used in various cultures to grow crops in desert areas. Beds do not need to be raised where soil is sandy.
For areas that also get periods of heavy rain, make a small break in the wall to allow extra water to run away when it is not needed, and repair the break after the wet season.
Water in some parts of Australia can contain different types of salts, and some food plants can't grow well in soils with 'salty' water. These plants include: French beans, broad beans, peas, lettuce, parsnip, radish, sweet potato, strawberries and raspberries, as well as avocado, apple, pear, almond, peach, plum, apricot, and citrus trees. Where the water supply is 'salty', save some drinking or rain water for seedlings and new plants of these varieties until they are making good growth.
You can help sensitive plants to grow better where water or soils are saline by making sure your garden beds contain plenty of compost, as compost limits the amount of salts that plant roots absorb. You can also construct rimmed beds (see above) for your garden. However, in areas with salinity problems, allow a wide margin between the edge of your beds and your plants. Put mulch around your plants, but keep the margin clear of mulch. Flood the beds with water when irrigating. This will push the salts towards the margin area, away from the plants.
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Try to vary the type of organic mulch you put on your garden to make sure that the topsoil receives a good range of minerals as the mulch breaks down.
MULCH IN WINTER
In most parts of Australia, mulch can stay on beds all year round. The decision to keep mulch on garden beds during winter will depend on individual situations. Organic mulch remaining in autumn keeps soil slightly warmer, thus prolonging the growing period.
A cover of straw or mulch hay will protect deciduous or sensitive plants, including artichokes, asparagus, French tarragon or strawberries through winter in very cold areas.
Further information for supervisors on types of mulch and in which situations to apply it, can be found in Easy Organic Gardening and Moon Planting pp 168-172.
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