Gardeners Supply Plant Care & Gardening Advice/Tips/Secrets @ HortChat.com®

I have got a serious white fly infestation in my front yard container garden. I have tried insecticidal soaps to no avail and live lady bugs. My aphids are gone but the white flies seem to multiply. This is an organic garden so I do not want to use serious pesticides. Any suggestions?

Whitefly are tiny white mothlike insects (adult stage) that fly when the plant is shaken. They can be found on the underside of leaves along with yellowish bumps which can resemble scale but are the nymph stage of the whitefly. The obvious symptoms of whitefly is the white cloud of tiny flies that emerges when the plant is distrubed as well as the sticky residue called honeydew on the leaves. Their sucking mouthparts feed on plants causing the leaves to turn yellow and die. In severe infestation, a sooty black mold may also be present from the honeydew. The general health of the plant is compromised, it becomes weak, produces pale, stunted and distorted growth, which eventually leads to death.

Whitefly are difficult to control because they reproduce so quickly (average life cycle is 30-34 days) and frequently build up a resistance to pesticides; therefore you need to be vigilant when it comes to treatment. Try repeated sprayings of insecticidal soap every 5-7 days for at least two weeks and make sure you spray the undersides of the leaves. In addition, try Vapona strips, yellow or blue sticky fly tape, ( a color that they are attracted to) hung above the plants. This will help reduce the adult whitefly population. A natural spray solution recommended by Rodale consists of 1 cup isopropyl alcohol mixed with 1/2 TB of insecticidal soap in 1 quart of water. Apply once a week for two weeks. Don’t use on hairy or waxy plants.
Some people have even tried vacuuming white flies off the leaves or spraying the plants vigorously with water to knock them off.
As a last resort use botanical poisons that are plant derived like  Neem  or a pyrethroid spray Pyrethrum that paralyzes whiteflies on contact.  Ryania is a mild alkaline contact insecticide that will not harm beneficial insects and leaves no residue.

To use Neem oil -mix 1 ounce (2tBsp) of Neem oil and 1 1/2 tsp. of diswashing detergent to 1 gal. of water. It works on the crawler stage, smothers the eggs and regulates insect growth. Several applications every 5 days may be required. Some plants can be sensitive to Neem oil and develop phytotoxicity. Follow safety precautions and manufacturers recommendations when using any chemicals. *Loggee’s

Forcing Spring bulbs

It’s nice to have a pot of blooming bulbs in the dead of winter to remind us of the promise spring yet to come.

Many bulbs can be forced to grow indoors in the winter. Spring bulbs such as; daffodils, hyacinths and tulips are the most popular but others like crocus, squill, grape hyacinth and Dutch iris can also be forced for indoor bloom.

Potting bulbs
When forcing tulips, make sure the bulbs are firm, free from soft spots, white mold, cuts and bruises. Fill the container 3/4 full with a well-draining potting soil mix and place the bulbs close together with pointed tips up and flat side facing out. The tips of the bulbs should be 1 inch below the top of the container. This allows room for root expansion and easier watering. Fill in additional soil mix around the bulbs and water well until it drains from the bottom. A 6 inch pot will accommodate 5-7 tulip bulbs, 3 hyacinths and 6 daffodils. Cover the container with plastic to keep the soil slightly moist during this cool period (optional). Be sure to mark your containers with the planting date.

Chill time
Chill the potted tulip bulbs in a cold basement, cellar, garage or refrigerator at 35-48F for 12-16 weeks. Cold treatment is varies according to type of bulb: on average, Daffodils require 12-13 weeks, hyacinths 10-14 weeks and smaller bulbs (grape hyacinth, crocus) 8-9 wks. Not enough chill time can produce short, distorted flowers. If storing bulbs in the refrigerator be sure there are no fruits or any other vegetation that emit ethylene gas as this can damage the flower inside the bulb.

Forcing bloom
The trick is to fool the bulbs into thinking that winter is over and its time to start growing.
After the cold treatment, check for white roots at the bottom of the pot and new top growth. Slowly, bring the container to warmer temperatures (55-70F) and indirect light and start watering. Once exposed to sunlight, the light yellow/green shoots should start to green up and grow. From this point on, it should take 2-4 weeks to bloom.

Flowers will last 10-14 days depending on temperature and sun exposure. The cooler the temperatures the longer lasting the flowers will be. Avoid exposing the flower to direct sun.
If you stagger planting time every two weeks and you will have flowers throughout the better part of winter.

Instead of discarding your poinsettia after Christmas, take on the challenge of re-blooming it for the next year.

Here’s what you need to do.
Maintain and water the plant indoors until March to May. If the plant becomes leggy and bare cut it back to 4-6 inch stems in Feb/March. This will stimulate new growth from the buds in the leaf axils. Place the plant in a sunny spot with temperatures of 60-70F. Start feeding your poinsettia with a well-balanced houseplant fertilizer every 2-3 weeks and continue throughout the growing season. Once new growth starts to show, repot the plant in fresh soil and a larger pot if needed.

In mid-May/June, move your poinsettia outside (when night temps are above 50F) in partial shade, protected from the afternoon sun. You can sink the pot into your flower bed. Be sure to rotate the pot periodically so the roots don’t grow into the soil.
If the plant gets tall and misshapen pinch back the lateral shoots between July-August to shape the plant. The cuttings can also be rooted as new plants.

Initiate blooming
In the fall, when temperatures get below 45ºF for an extended period bring your poinsettia indoors. Poinsettias need short days and long nights to bloom. To initiate blooming you must expose the plant to 14 hrs of uninterrupted darkness (no cheating, even a small amount of light will break the cycle) followed by 10 hrs of bright light for a period of 8-10 weeks starting late September. Keep it in a room that you don’t use in the evening or place it in a black plastic bag or a box. (Don’t forget to take it out during the day.)

Poinsettia needs a cool, bright location during the day with temperatures ranging from 60 to 70F. Water when the soil surface is dry and drain any excess water. Don’t let your plant sit in water as that can cause the roots to rot. Continue to fertilize lightly every 4 wks with 15-16-17, or 20-10-20 until flowering begins (mid-December). Because of lower light conditions and slower growth reduce the amount of fertilizer. Once the plant is in bloom stop fertilizing and resume again in March.
It takes 60-85 days depending on variety, temperature and light intensity for the bracts to show color.                                                  

Reblooming poinsettia requires persistent attention but can be a  rewarding challenge!