Helpful Lighting Hints for Better Growing Results

Helpful Lighting Hints for Better Growing Results


Light Intensities:

A. For germinating seeds and rooting cuttings:

10 lamp watts per square foot of growing area. The light source should be 6″ to 8″ above the soil or planting media. Recent studies indicate that if seeds are exposed rather than being lightly covered, a high germination percentage is obtained. Another system that may be used is to cover the seeds lightly with soil, vermiculite or perlite and then comb or scrape the surface lightly after soaking the cover medium. This allows for better penetration of light as well as incorporating air in the seed areas.

NurtureLite fluorescent bulbs are particularly useful for germinating seeds for outdoor spring planting. When the NurtureLite seedlings are to be transplanted to the outdoor environment, proper steps must be taken to harden the seedlings. This is accomplished by gradually reducing the temperature and keeping the plants somewhat drier than usual until they are acclimated to outside conditions. A common procedure is to expose seedlings to the out of doors during the day and take them in for the night until they are firm enough to leave outside permanently. It may take about one and a half weeks to fully harden the seedlings. During the first few days, however, the young plants need protection from sunlight by providing some type of shade. An important factor to remember when hardening plants is to have air circulation, especially if they are in protected areas. This will prevent buildup of high temperatures, and thereby reduce the wilting of the young seedlings.

B. For low energy growing plants:

15 lamp watts per square foot of growing area. The light source should be 12″ to 15″ above the plant tops. Many household plants fall in this classification.

C. For high energy growing plants:

20 lamp watts or more per square foot of growing area. The light source should be 12″ to 15″ above plant tops. Plants such as chrysanthemums, carnations, roses, tomatoes, beans and most vegetable crops fall in this classification. When these plants are grown in enclosed areas where there is no available sunlight, 10 to 20 percent of the total wattage should be provided by incandescent lamps or the NurtureLite bulbs. These lamps provide the far red radiation that is important for normal plant development with high energy crops.

Length of Light Periods (Photoperiod):

A. For the germination of seeds and rooting cuttings:

A light period of 16 hours produces satisfactory results. With newly germinated seedlings and rooted cuttings, prior to transplanting, a longer light period of up to 20 hours may be used with good results.

B. Short day plants – Duration of light:

Gardenias, Poinsettias, Chrysanthemums, Christmas Begonias – 10 to 13 hours

C. Long Day Plants:

China Asters, Calceolaria, Coreopsis, Dahlias, Nasturtiums, Annuals – 14 to 18 hours

D. Day Neutral Plants (Not affected by Photoperiod):

Roses, Carnations, Begonias, African Violets, Gloxinias, Geraniums, Coleus – 12 to 18 hours

Cultural Requirements:

A. Plant ambient temperature:

For most plants, the temperature during the light periods should be approximately 70° – 75° F, and during the dark periods 60° – 65° F.

B. Plant environment humidity:

From 50% to 60% humidity is recommended. Also good ventilation is necessary for best growth environment.

C. Plant spacing:

Space out the plants to encourage disease-free plant growth and to promote strong roots, stems and foliage.

D. Plant watering:

Water plants when the lights are on. At this period the temperature is rising, and there is a greater need for water by the plants.


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