CLASS NOTES ON WATERING YOUR VEGETABLE GARDEN

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1 CLASS NOTES ON WATERING YOUR VEGETABLE GARDEN Keys To Vegetable Gardening Soil Sun Proper Plant Selection Watering Seasonal Planting PRIMARY FACTORS THAT IMPACT WATER NEEDS Soil (Mix, Ground, Raised Bed, Container) Sun and Temperature Plants (vegetables, trees,) Mulch or Lack Of Frequency of Watering Delivery System Watering Techniques Watering your garden effectively is all about knowing its needs. Over-watering is as harmful for plants as providing too little water. A variety of methods can be used, ranging from very simple to complex. The simplest solution is to hand water the plants with a garden hose or a watering can. More complex systems use sprinklers, and the most complex systems use drip irrigation. What you use depends on the size of your garden and the amount you are willing to spend on the system. Water Conservation and Application Techniques Group plants with similar water needs in the same section of the garden for easy irrigation.

2 Cucumber, zucchinis, and squash, for example, require similar water applications. Protect plants and soil from wind with windbreaks to reduce evaporation Mulch 3 inches or more Watering Can: Although old-fashioned, watering each plant by hand allows you to effectively target and evaluate individual patches of soil and the spout ensures the water goes straight to the roots. Soaker Hose: Soaker hoses are a great and inexpensive alternative for gardens. Made from recycled tires, they sweat water through millions of pores along the entire length of the hose. They allow almost no evaporation, can be hooked up to a timer, are easily buried under mulch, and require relatively little upkeep. Rule of thumb for When to Water 1. water is most critical during seed germination 2. the first few weeks of development 3. immediately after transplanting 4. during flowering and fruit production. Use of a drip system on a mulched garden may reduce water need up to 50% check soil moisture regularly. Squeeze soil in your hand; if it sticks together, it is moist and should not be irrigated. If it does not stick together, then it is time to irrigate. Irrigate in the morning when temperatures are cool but rising. A house plant water meter is a useful tool to evaluate the irrigation needs of the garden Control weeds that compete with vegetables for water Sprinkler Irrigation

3 water needs of the vegetable Garden are different from grass, Garden should be on a different irrigation zone than the lawn. Water use will be low in the spring when crops are small and temperature are cool and will increase as the temperatures rise and crops come into bloom. wets the entire soil surface, weed seed germination will be high. discouraged on vegetable crops prone to foliar diseases, like tomatoes, peppers, and potatoes subject to Early Blight. The splashing water spreads disease organisms and water on the leaves creates favorable conditions for disease development. As a rule of thumb, vegetables use around ¼ inch of water per day during moderate summer weather. If the garden is watered every four days, apply one inch of water per irrigation. The gardener can quickly learn how long to run the sprinklers by measuring the amount of water in several straight-sided cans placed around the garden. Delivery rates depend on the type of sprinkler head and the spacing in the garden. Mulched gardens will be lower in irrigation need. Drip Irrigation: With over 90% efficiency, drip irrigation is the most effective of all watering systems. Drip irrigation consists of tubes with a release point next to each plant. If a plant no longer needs water for the rest of the season, a goof plug can be inserted to stop water flow to that area. This system can be set on a timer, uses a battery to regulate flow, and a backflow prevention device blocks the water from contaminating potable water. Drip Irrigation Several different drip systems are available with micro sprays, bubblers, and soaker hoses. Soaker hose type of drip system allows water to seep out the entire length of the pipe. It is easy to use in a traditional row style or raised-bed garden. Ideally, the soaker hose is placed on the soil surface under the mulch. Alternatively, it should be buried a couple of inches into the soil to protect the hose from breakdown by sunlight. For uniform water delivery, keep runs short, generally less than 25 feet but never longer than 50 feet. The ground must be reasonably level. On slopes, run several short lengths.

4 Keep the pressure low by only turning on the valve part way. The water should drip out of the hose, not spray. High pressure may rupture the hose. Run time will vary with the brand of hose, water pressure, and spacing. Soaker hoses typically run for only 10 to 15 minutes to thoroughly water the soil. Some brands have inserts into the hose fitting to reduce pressure. These brands may need to run for an hour or more to adequately water the garden. Drip systems can be easily automated with a multi-zone controller like the lawn or a single zone controller that connects at the tap before the hose. Watering needs will vary depending on container size, ambient temperature, wind, sunlight, and humidity. You can count on watering most container vegetable plants daily during the summer months. The growing media should always be moist, but not soggy. Add water slowly until you see it drain out the bottom (except for selfwatering types.) Use a watering can or nozzle on the end of a hose that produces a soft stream of water. Eating quality and yield will be greatly reduced if plants are allowed to wilt due to a lack of water. Drought stress will kill feeder roots and slow plants down. Small containers dry out more quickly than large containers. Use a saucer to catch excess water. Large, mature plants need more water than seedlings and young plants. Micro-irrigation with soaker hoses and drip emitters is efficient, convenient, and relatively inexpensive. You can water all of your containers automatically using a series of drip emitters on a timer. The critical watering periods for selected vegetables Asparagus needs water most critically during spear production and fern

5 (foliage) development. Less water is needed after ferns reach full size. Cole crops (broccoli, cabbage, cauliflower, collards, Brussels sprouts, kale, and kohlrabi) need consistent moisture during their entire life span. The quality of cole crops is significantly reduced if the plants get dry anytime during the growing season. Water use is highest and most critical during head development. Corn water demand peaks during tasseling, silking, and ear development. Water stress delays the silking period, but not tasseling. Under mild water stress the crop may tassel and shed pollen before silks on ears are ready for pollination. The lack of pollination may result in missing rows of kernels, reduced yields, or even eliminate ear production. Yield is directly related to quantities of water, nitrogen and spacing. Tomatoes, Peppers, and Eggplant needs water most critically during flowering and fruiting. Blossom end rot (a black sunken area on the bottom of the fruit) is often a symptom of too much or too little water. The tomato family has a lower water requirement than many vegetables and plants are often over-watered in the typical home garden. Vine crops: cucumbers, summer and winter squash, and assorted melons need water most critically during flowering and fruiting. Vine crops use less water than many vegetables and are often over-watered in the typical home garden. Beans have the highest water use of any common garden vegetable.

6 They use 0.25 to over 0.50 inch of water per day (depending on temperature and wind) during blossoming and fruit development. Blossoms drop with inadequate moisture levels and pods fail to fill. On hot, windy days, blossom drop is common. When moisture levels are adequate the bean plant is a bright, dark, grass-green. As plants experience water stress, leaf color takes on a slight grayish cast. Water is needed at this point to prevent blossom drop. Carrot and other root crops require consistent moisture. Cracking, knobby and hot flavored root crops are symptoms of water stress. Lettuce and other leaf vegetables need water most critically during head (leaf) development. For quality produce these crops require a constant supply of moisture. Onion family require consistent moisture and frequent irrigation due to their small, inefficient root system. Peas need water most critically during pod filling. Potato tubers will be knobby if they become overly dry during tuber development. Avoid these three common watering problems Frequent, shallow watering promotes root development in the surface layers of the soil. Plants with shallow roots are very susceptible to drought. Soil should be damp to 6 inches deep after watering. Damp not soaking wet. Over watering can drown plants by filling up soil pores with water, leaving little or no oxygen for plant roots. Also, excessive watering leaches away nutrients and can contribute to groundwater contamination. Soil should be damp to 6 inches deep after watering. Damp not soaking wet.

7 Postponing irrigation after plants show signs of needing water can damage plants very quickly in hot weather. Observe your plants every day or two and respond to their needs promptly. Soil should be damp to 6 inches deep after watering. Damp not soaking wet. Preparing a Fall Garden Select a Garden Site: Consider the plant needs of: Sunlight Soil Water Accessible Air Movement Vegetables need sunlight, proper temperatures, fertile soil and water for best growth Selecting a location for a vegetable garden is critical to good vegetable production. The vegetable garden site should have the following qualities: 6 to 10 hours of full sun per day; a source of water; deep, well-drained, uncontaminated soil Amend Garden Soil with decomposed Organic Matter the routine addition of organic soil amendments such as compost will optimize potential yields and produce quality Be sure that the organic matter is thoroughly cultivated into the soil. Leaving chunks of organic matter will interfere with seeding, root spread With adequate organic content in the soil, the garden should be able to go two to seven days between irrigations. Select the vegetables you want to grow. Grow only what you will EAT Draw a diagram of the garden site. Record what you grow

8 Dates of planting, variety, spacing, weather, fertilizing rate, watering Cabbage, broccoli, Brussels sprouts, kale, cauliflower and kohlrabi, spinach, collards, and similar greens are all good crops for fall gardens. They're best started from transplants but can be direct-seeded, too. If you seed them directly into the soil, keep the ground moist while it's still hot to give them a good start. Radishes will mature in about four weeks. Beets and Swiss chard, both hardy crops, mature in about 60 days. Carrots can be seeded in September through October for harvest in the spring. Onions are usually transplanted in November for harvest in April and May.