Large Pores are Good! The key to success in growing plants lies in successful soil preparation. The soil is the source for water and nutrients that are necessary for plant growth. Nutrients are found in the particles that comprise soil while water resides in the spaces or pores between the soil particles. The important thing to know is that roots need air to absorb both nutrients and water. If the pores are always filled with water (such as in poorly drained soil or as a result of over watering) there is no room for air. So what gardeners want to do is to create large (macro) pores that drain quickly making room for the air roots need to take up water and nutrients. We do that by incorporating organic matter into the soil which binds together particles into aggregates that leave macro pores. Organic matter is also food for soil microorganisms, earthworms and other soil inhabiting critters that convert the organic matter into plant food. They also turn mulch and other dead plant matter such as leaves into organic matter and finally plant food. This process consumes the organic matter so that new sources must continually be added such as more mulch or compost or leaves or grass clippings or some combination of all of the above.

Feed Me! Feed Me! Feed Me! No matter how much organic matter we provide it is generally not nearly enough to provide all of the nutritional needs of a plant. Therefore supplemental feeding is required. We advocate the use of organic sources of nutrients because they help feed the essential soil critters and are broken down slowly like a slow release capsule. They also provide all of the nutrients required including both macro and micro nutrients as well as other elements that might benefit a plant even if we don抰 know about it yet. Your plants should be dark green in color and have leaves all along the stem. If not they are hungry. Feed them. The time to feed them is in the late winter or early spring so that the soil critters can break down the nutrients in time for spring growth to begin. Also, if you want to encourage rapid growth such as a plant that will serve as a screen you can fertilize again in August to encourage an additional flush of growth in late summer and early fall. Don抰 fertilize any later than early September because you want growth to stop before cold weather comes so it will have time to harden off so it won抰 be damaged by freezing weather.

Thirsty! Water is required to move nutrients, enzymes and other stuff from the roots of the plant up into the stems and leaves where it is released into the air in the process called evapo-transpiration. Therefore a constant supply is needed. However, as we discussed before the soil can't be constantly saturated with water because all the pores would be filled up and we know why that is bad. So water needs to be added as needed. Since one of the functions of roots is to take in water they will grow in search of sources of water. We want to encourage the roots to do their jobs to the best of their abilities so we let them go until they have used up all of the water they can find. When that happens the leaves start to wilt because there isn't enough water to fill them up. So then we have to add more water. when we do water we want to water deeply by allowing the water to run for a long time. The minimum water needs for new plantings is 1inch of water per week. It takes at least 2 hours for a typical sprinkler to put out 1inch of water. Water deeply but not frequently. Get to know your plants and they will communicate to you when they need water.

Let There Be Light! Plants also need light for photosynthesis. Some plants needs lots of light (sun loving plants) some have learned how to use light more efficiently( shade tolerant, not loving, plants). Plants that need lots of light will not do well in shade. Plants whose natural habitat is under the canopy of trees will most likely burn up in the hot Georgia summer sun. Along with light tolerances plants also have heat and cold tolerances. We talk of a plants hardiness which refers to the minimum cold temperature it can stand before it dies. Now we are becoming aware that some plants can tolerate only so much heat before they die. It is helpful to find out where a plant originated from to determine if it might live in your garden. For example a plant that is native to the Alps will probably not be able to tolerate our summer heat while a plant that originates in Jamaica will probably not survive our winter. Some times we can find a place in our garden where it stays just a little cooler in the summer or a little warmer in winter so a particular plant we love can survive. These places are called micro climates. They allow us to expand our plant choices. The city itself is a micro climate that is warmer than the surrounding suburbs and with our walls and sidewalks that absorb heat we can grow plants that cannot be grown in Alpharetta for example. Conversely, it is hotter in the summer putting more stress on some plants.

?The Urban Gardener, Inc. 2005

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