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North Mississippi Gardening Tips
April, 2007

Container Gardens

By the middle of this month you can safely drag all your frost tender pot plants back outside. Please, please do not stick them out in full sun, even if they were grown outdoors in full sun last summer. After being inside all winter under a lower light situation your plants are not ready for  (acclimated to) full sun. Think about it. Would you bare your hide to the full force of the sun all day without some period of gradual adjustment? Of course not, because if you did you would wind up looking like a big blood blister!--same thing with your plants. The leaves will bleach out or sunscald at the least, or at the worst the plants could be burned so badly they would die. Gradually increase the exposure of your pot plants to their new environment to avoid these problems. Work you way up to a full day of sunbathing for you and your plants!

Trees and Shrubs

Prune any wayward, diseased, or dead branches from spring ornamental trees only after all petals have fallen. Likewise, wait until petal fall to fertilize these trees. It is always best to base fertilization on a soil test, but in case you haven’t done one lately for your spring-flowering trees, here is a general recommendation: one pound of 5-10-15 fertilizer per inch circumference of the tree measured three feet above the ground. For evergreen trees, use a slow-release formula at a rate of one pound of fertilizer per inch circumference of the tree, measured three feet above the ground.

Vegetables and Herbs

I bet if you are a vegetable gardener you are already enjoying some of your cool-season vegetables, such as greens, radishes and others. It’s time now to start thinking about your warm season veggies.   But, until the ground warms to above 60 degrees fahrenheit, most warm season vegetables including beans, squash and corn will not germinate reliably. If you’re planting watermelon, cantaloupe or okra the soil temperature should be at least 75 degrees for good germination.  By the middle of this month the ground should be sufficiently warm for good germination of most warm season vegetables. 

Insects are attacking vegetables now. Aphids, flea beetles and caterpillars are just a few of the critters chomping away.  When you have to spray your vegetables always read the label and do not harvest the vegetable before the recommended days to harvest from time of application has passed. 

To help maintain soil warmth and deter insects, you can cover the seed beds with floating row covers. You can purchase these from the local farmer’s co-op, garden center or nursery. Vegetable transplants such as tomatoes and peppers will not grow substantially until day temperatures are consistently 75 degrees Fahrenheit or higher. Test after test has shown that tomatoes planted when soil and air temperatures are warm bear fruit not significantly later than unprotected plants set out earlier during cool weather.

Flowers

With garden centers and nurseries full of plants, it is time to get out and purchase some new flower “pretties” for your yard and garden. With that in mind, here are some shopping tips to assist with your selections.

Smart Shopping for Annuals
These are purchased for fast growing, long lasting flowers or foliage. It is important to select healthy plants that have bushy growth that fills the pot. Foliage should be an even green color without obvious disease spots or insect damage.  Even though it is tempting to purchase a plant in flower, in many cases, this should be avoided. A plant in flower, in some cases, has been fed a high nitrogen fertilizer to spur rapid growth and development—this can result in a plant that is a heavy feeder. When these plants are transplanted into the garden and their high-maintenance diet is not maintained they can quickly lose vigor.  Look for plants that are just beginning to flower or are in bud. Sometimes plants are flowering because they have been in the pot too long and are too mature and leggy.  These should be avoided, or if purchased, should be cut back to encourage densely branched new growth. Examples of these are verbena, marigold, salvia, and celosia.  Continue pinching these plants to get that bushy plant with many flowering stems. Annuals like petunia and impatiens really do benefit from pinching to get bushy growth.

Smart Shopping for Perennials
These are purchased for their longevity in the garden and their season of attractiveness, whether that is foliage color or blooms. Since these plants will be residing in your garden for years to come, selection of well-rooted plants with a good rosette of healthy foliage is important. Most perennials will not be flowering in the pot, so you should be familiar with the mature height, width, bloom color and other characteristics of the plant before you make your selection. Sometimes this is all on the label. Most of the time it is a good idea to talk to the nurseryman or garden center help who can answer questions as to how these plants will perform.   You may ask their permission to pop the plant out of the pot to examine the roots, or ask them to do it for you.  The roots should be a light tan or off white color and be plentiful, but not circling the root ball in a tight mat—this indicates the plant has been held too long in the pot and is pot bound. If you purchase a pot bound plant, before you plant cut away the circling roots and tease the root ball apart to encourage outward growth of the new roots. 

Lelia Scott Kelly, Ph.D., writes North Mississippi Gardening Tips monthly and is a Horticulture Specialist with the Mississippi State University Extension Service. Her office is in the North Mississippi Research & Extension Center, Verona.