Raised Beds Versus Flat Beds
For efficient water conservation, prepare a soil surface for maximum water penetration. Planting in a flat surface is preferable to any combination of the traditional raised mounds, beds or hills. These rounded/raised structures, once dried out, are very difficult to wet again. Water runs away from the root zone of the plant and is wasted. Always create a small ridge of soil around each hill to hold any applied water so it can slowly soak into the root zone. When using raised mounds or beds, do likewise, or cover with a layer of compost or mulch to hold rain and irrigation water (if your soil is prone to flooding or is in a poorly drained wet area, raised beds/hills may be necessary).
Mulching and Soil Tilth
Managing soil tilth to include additional organic matter and compost will promote water penetration and retention. For maximum water conservation, apply compost to the soil surface as a mulch after transplanting and seeding. This will allow the cold spring soil to warm-up before the application of the cooling mulch layer, thus enhancing seed germination and early spring transplant vigour. The surface compost layer will conserve water during the hot summer season and keep root systems cooler. The compost layer can be worked into the soil at the end of the growing season or in the early spring before planting.
Cultivating and Weeding
A number of good gardening practices will help in conservation efforts. For example, don’t plant in soils that are too cold–seeds won’t grow satisfactorily, and water will not be properly absorbed. From the start, weed control is very important in your garden. Weeds waste water, and they compete with vegetable plants for nutrients and sunlight. For efficient water use, maintain excellent weed control in your garden. If you are not using a surface mulch, cultivation of the soil should be shallow. Excessively deep tillage or hoeing not only damages plant roots but also allows moisture to evaporate. Very shallow weed control with a scuffle or push hoe is best. (A scraping action with the scuffle hoe is preferable.)
Install rain barrels at the base of your down spouts and use this source of water to irrigate as many plants as possible.
Use Water Wisely
Root zones. When you use water, try to concentrate it in the plants’ root zone. The less water you apply between the rows where roots can’t use it, the less water you lose to evaporation. In addition, water from a sprinkler won’t all reach the soil surface because of evaporation – a loss of up to 25%. Several techniques will help place the water in the root zone where it’s needed:
- For crops like squashes and cucumbers that are usually grown in a hill, create a depression in the centre of the hill and surround it with a ridge that will prevent water from running away from the root zone.
- You can irrigate individual plants like tomatoes, peppers, eggplants, flowers and bushes in a similar manner: create a small depression for each plant.
Sprinkler irrigation. If you use this system, minimize water losses by:
- using a sprinkler that will cover the garden only, not the surrounding area;
- watering early in the morning or in the evening when the air is cooler, the wind is low, and water pressure is better on municipal systems; and
- using a rate of application that permits all water to soak in and not run off the garden area.
Soak the soil. When you water, thoroughly soak the soil to a depth of 6 to 8 inches and do it infrequently. Depending on stage of growth and temperatures, watering once per week is usually sufficient, and only then if you do not receive adequate rainfall during the period.
Try closer rows. A smaller area gardened more intensively will produce more vegetables (and flowers) in relation to water usage. You can grow many vegetables much closer together than in the traditional 2 1/2- to 3-foot rows. You can place radishes, onions, beets, carrots, etc., in rows as close as 1 foot apart. This way, you make better use of the water you apply in the root zone. In addition, a soil shaded by vegetable leaves loses less water by evaporation to the atmosphere.
Container planting of vegetables and flowers will use more water than in-ground gardening. Containers dry much faster than garden beds and rows. Nevertheless, when using containers, try insulating them by placing the plant pot inside a larger one and filling the space between the two containers with dried leaves, soil or compost.