The potted annuals and herbs on my patio are starting to look pretty sorry. I'm starting to plan fall flowers to take their place. It occurred to me: can I reuse the potting soil already in the containers and save a few dollars, or do I have to buy fresh bags?
You can certainly reuse last season's soil. But understand that, while you're saving money, to have successful plants you will have to spend some extra time - time spent improving the soil's texture and replenishing its nutrients.
Be forewarned. If your plant died of anything other than old age and exhaustion, it's best to take that soil straight to your compost pile. The heat of the composting process will be high enough to kill off most bacteria, fungal spores or insect pests that caused your existing plant to keel over. Colorado State University offers several ways to sterilize used soil, but that gives "making mud pies" a whole new definition that I'm not willing to explore. If this intrigues you, the instructions are at www.colostate.edu/depts/CoopExt/4DMG/Soil/sterile.htm.
Start with aerating the soil to make it light and fluffy. A good soil is dense enough to support the plant, to hold nutrients and to allow air and water to move through it while retaining moisture for the roots. Having been in a container all season, the potting mix has become compacted with no space between the granules for air. Simply turn the soil several times and break up any hard clumps. Look for any insect pests or their eggs, and remove anything that might impede root development including any plant remains, especially roots.
Next, concentrate on replenishing the nutrients that were either used or leached out. There is any number of soil amendments to use, like bone meal, feather meal, poultry manure or store-bought or homemade compost. Peat moss is the most commonly used organic material. The organic material in soil will decompose so you will lose some volume. You may have to add extra soil to your container when this happens.
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Adding builder's sand, coarse sand, ground pine bark or Perlite will increase the air space of the mix while improving water drainage.
If you have a lot of pots to fill, consider making your own mix from scratch. A list of materials and "recipes" appropriate to a variety of plants is available at solutionsforyourlife.ufl.edu/hot_topics/lawn_and_garden/homemade_potting_mix.shtml.
It's too hot to hand-pull weeds, and they've sprung up everywhere. Is there a weed killer that I can spray around the plants in my borders this time of year?
Hold on. October is right around the corner … sort of.
A bed or border with shrubs, mixed perennials and annuals, will probably contain the entire spectrum of weeds - broadleaf, grass and nut sedge. There are only a few postemergence herbicides that will be effective on all types.
A nonselective postemergence herbicide will kill all green plants, regardless of species. Glyphosate (Roundup), Glufosinate (Finale) and Diquat (Reward) are examples that can all be used as a spot treatment.
To increase the effectiveness of an herbicide, water the day or evening before treatment, or time the application after a rainfall. Before using these products, be sure to read and follow label instructions and safety guidelines.
It's summer. Weeds are mature and harder to control. Its effectiveness is reduced when the weed is under drought stress, or has begun to produce seeds. You may even have to apply the product more than once. With weed control, timing is everything. It's easier to get them when they're young.
See more information on types of herbicides and how to use them at hort.ufl.edu/yourfloridalawn/weed_management_chemical.shtml.
I have two tall, beautiful eggplant plants that had lots of flowers all summer. But I've only gotten one eggplant. What did I do wrong?
You may have done nothing wrong at all. Eggplant is finicky. Too hot, too cold, too dry, too wet, too humid, too hungry - take your pick. And this summer has seen almost all the above.
Eggplant is a member of the nightshade family, and a close cousin to tomatoes, peppers and potatoes. Just as you don't plant tomatoes where last year you planted peppers, so should you avoid using the same space for your eggplant that you used one of its family members. Next summer, find a different corner of the garden, or grow your eggplant in a container.
Since your plants produced flowers all along, and you describe it as beautiful, it's probably not suffering from a disease or insect pests.
It might be an environmental problem. Eggplants need consistent watering. When stressed by lack of water, the blossoms dry up and drop off. One good, deep watering a week (or more in very hot weather) to encourage deep roots is better than several shallow irrigations. Watering is most important at the time of flowering, fruit set and fruit growth. Mulch to retain the soil's moisture will help, too.
The optimum temperature for eggplants to set fruit is 70 to 85 degrees. At 95, the plant will stop setting fruit altogether. Typically, eggplant grows best with seven to eight hours of sunlight. But our midday intense sun and heat can be an intolerable stress. Next year, consider a location that provides at least some relief from excessive heat.
The heat also impacts pollination. Eggplant is self-pollinating and usually the wind is enough to move the pollen down the pistil to produce a flower. However, if the weather is very humid, the pollen becomes "sticky" and clings to its place in the flower. Because the flower isn't pollinated, it drops off. You can pollinate the blossoms by hand with a small brush or cotton swab. Gently move the brush around inside the flower to help release the pollen.
The Florida Vegetable Guide lists July as the last month to plant eggplant in North Florida. If your plant is still healthy and has flowers, you might still be rewarded. The moderating fall weather ahead should improve the changes of more flowers and more fruit.
Paula Weatherby is a master gardener with the Duval County Extension Service and the University of Florida/IFAS.
