Eggplant Planting Guide

Eggplant Planting Guide

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Eggplant is an uncommon delicacy in Utah gardens, despite its relative ease of growing.  Mild flavor and savory texture make it an excellent addition to stir-fries, pastas, and other dishes. Purple, violet, green, or white fruits can decorate compact (2-3 feet tall), handsome, bushy plants. Plants almost look like miniature trees, with drooping violet flowers, and large, red-tinged leaves with their colorful and unusual shaped fruits.  In the same family as tomatoes and peppers, cool days and nights don’t agree with eggplant, so plant when days are long and hot. Eggplant grow very well in containers or raised beds.


Eggplant prefers a loose, sandy soil, that is rich in organic matter, well drained, and not too heavy. They also need full sun exposure. Before planting, incorporate 2-3 inches of well composted organic matter and 1-2 lbs of all-purpose fertilizer (we recommend “That’s All it Takes” complete fertilizer) per 100 square feet and work them into the soil to a depth of 4-6 inches. Heavy, clay-based soils must be amended with compost and organic matter to encourage and allow good root development. If you have heavy soil, we recommend 4-6 inches of organic matter and 50 lbs of Utelite or Zeolite per 200 square feet added to the soil each fall for multiple years to increase drainage and nutrient availability. Over time, you can create a better growing environment for your garden plants to thrive in and produce. Please see our information sheet “Preparing your Soil” for more detailed info on soil preparation before planting a garden.


Eggplant needs 60-95 days with nighttime temperatures over 65 degrees, so northern Utah growers need to start them indoors around the middle of March.  Seeds should be planted ¼ inch deep in a light, seed-starting mix, in whatever container is most convenient for you. Transplant when stalks are strong and have 6-9 leaves (generally they are ready to go outside by mid-May), but before blossoms or fruit begin to grow. Be sure to space the seedlings correctly when transplanting, with 24-36” recommended between plants as well as 36” between rows. Once planted, water the seedlings with Kangaroots root stimulator for quick root development. Use the Kangaroots every 4-5 days for the first 3 waterings for less transplant shock and to speed up early development.   To help protect the plants from late frost, and to increase temperatures around the plant, use hot caps or Wall-o-Water plant protectors over newly planted seedlings until weather permits, or the plants out-grow them.


Because of our short growing season, fast-maturing varieties work best in Cache Valley. Black Beauty is the traditional Italian style eggplant that most gardeners are familiar with.  Long Purple is an oriental style eggplant.  The fruits are long and slender, and it is not uncommon for them to reach a foot in length. Both varieties are prolific and vigorous under warm growing conditions.


Water eggplant deeply and frequently while trying to maintain even soil moisture.  Eggplant needs consistent watering to develop high quality fruits.  Use a soaker hose or drip system for uniform water distribution and water lightly every 5-7 days to maintain soil moisture during these essential growth stages.  A light compost mulch can help as well if daytime temperatures start to climb over 80 degrees.  Eggplant grow well in plastic mulch (clear or black) or weed barrier as it helps generate and hold more heat and retain more consistent moisture.


Apply ¼ cup per plant of “That’s All it Takes” complete fertilizer or Happy Frog Organic Tomato & Vegetable Food 4 weeks after transplanting to encourage and maintain vigorous plant growth and flower production. Place the fertilizer evenly just to the side of the plants in the row and work it lightly into the soil before watering.  Make sure to water it in! We also recommend treating your eggplant with beneficial microbes and mycorrhizae (Kangaroots or Myke). These added helpers bring nutrients and water directly to the plants that host them, making them stronger, more resistant to insects and diseases, and more drought tolerant.


Eggplant can be caged or trellised much like tomato plants.  As the fruits develop, they will become heavy and weigh down the plants, sometimes to the point of breaking branches and damaging developing fruits. Prune the plants minimally to remove some small fruits and allow others to grow larger, or let them flower freely if you prefer more, smaller fruits at harvest time.


Keep the weeds to a minimum with the use of plastic and organic mulches. We prefer Pro 5 weed barrier as it allows water and nutrients to pass through, but stops even the most difficult weeds as they germinate.  Treflan and Corn Gluten weed preventative herbicides are also very effective ways to stop weeds before they start, saving you hours and hours of weeding.  Be sure to control weeds when they are small to ensure damage is not done to the root systems when weeds are removed. Also, practice crop rotations to discourage pest problems. Aphids, Potato Beetles, and flea beetles can all pose problems, but quick treatment with Ferti-lome Triple Action or Broad Spectrum Insecticide can bring them under control if treated early.


Harvest in mid to late summer,  when fruits are firm skinned and glossy. Once they lose their sheen, the fruits become bitter tasting. Use a knife or pruner to cut the fruits from the plants to avoid damaging the stem and disrupting the growth of remaining fruits.

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