(2/7) I've had my seed catalogues for over a month, some since Christmas. I'm getting tired of eating bagged salads. When can I start gardening? . . . Well, I need to be patient a little longer. Right now, though, I can layout my garden on paper and think about starting my seeds.

Planning is an important aspect of gardening. It's tempting to skip this step, but over time, I've found it to be one of the more important steps. Why? An extremely important reason is to be sure you are rotating your vegetables. Since plants have different nutrient needs, planting the same plant families of vegetables in the same space year after year will use up certain nutrients in that area, even using fertilizer. Potatoes, tomatoes and other members of the family Solanaceae, for instance, require a lot of nitrogen relative to other nutrients. Soil tests can tell you the amount of nitrogen you need to amend your soil after a few years of potato cultivation, but it cannot tell you what micronutrients are depleted.

Using compost will help with the loss of micronutrients but think about insect pests. If you don't rotate families of vegetables, insects that specialize on one type of vegetable can easily find their favorite meal again. After feeding on your potatoes during the summer, potato beetles overwinter in the soil nearby. When those hungry beetles wake up, they will find breakfast ready, allowing them a quick start on the next generation of potato beetles.

Let's say the insects are not a huge problem, and your garden is small. There are still diseases that affect a plant family remaining in the soil, especially if you didn't remove every bit of the plant at the end of last season. Potatoes and tomatoes are both susceptible to early and late blights. If any infected plant material gets left behind over the winter the spores can quickly find their host when the area is replanted with potatoes and tomatoes this year.

A practical reason to plan your garden is to have a realistic idea of what your garden will look like. On paper you can move plants and beds. You can anticipate spacing and how much room your vegetables need. You can make sure you planned enough area for your family's favorites as well as any new varieties of old favorites or new vegetables you want to try. If you decide to trellis cucumbers or beans, you can decide if they leave enough open space to try a new heat tolerant variety of lettuce.

You have finished your plan, ordered your seeds and you still feel the need to get your hands dirty and smell the soil. When can you start to plant? What needs to be started indoors and what should wait until the soil is workable and warm enough to encourage germination? Swiss chard, members of the cabbage family - cabbage, broccoli, kale, etc. - and several herbs can be started indoors in early March. Tomatoes, peppers and warm weather plants that are set out after Mother's Day should be started indoors in early April.

It is tradition to plant peas and potatoes on St Patrick's Day, March 17, but potatoes really get the best start if they are planted when the soil reaches 40˚- 45˚F. Other direct sown, early vegetables and their best soil germination temperatures are lettuce (40˚- 80˚F), peas (45˚- 75˚), turnips (55˚- 75˚), radishes (45˚- 80˚), carrots (55˚- 75˚), beets (50˚- 75˚), kale (55˚- 75˚) and spinach (45˚- 75˚). Perennial vegetables to plant in late March are asparagus, rhubarb and horseradish.

When do you plant your started vegetables? If you are not planning to use measures to keep plants warm and cozy, you need to pay attention to last freeze dates and last frost dates. Last freeze dates are quite variable in time and location, whereas last frost dates are generally accepted as reliable. Several reliable internet sites have this information. (Check the last frost date by zip code or view the USDA Plant Hardiness Zone Map at http://planthardiness.ars.usda.gov/PHZMWeb/Default.aspx)