RX for Healthy House Plants – Part 3

Greenhouse Plants

Part 1 | 2 in this 4 part series

AZALEA Soil: pure acid peat or soil mixture with a high peat or leafmold content. Temp: 55′ to 60°. Light: full sun. Bloom Requirements: failure to bloom due to too high a temperature; plants brought in from outdoors in the fall should be kept in a cool but light room at 40° to 50°. In January raise temperature to 55° to 60°. Insects: aphid, red spider mite, cyclamen mite, mealy bug, lace bug, slugs and snails. Diseases: stem rot, chlorosis (not a disease but so listed for convenience). More on Azalea Care.

CALCEOLARIA Soil: 14 each of soil, sand, manure, and peat or leaf-mold. Temp: 50° to 55°. Light: full sun from November to – March. Protection from full sun for remainder of year. Bloom Requirements: failure to bloom due to temperatures above 60°; plant produces foliage above 60° but must have about three months at a lower temperature for bud formation and development. Insects: aphid, thrip, mealy bug, red spider mite, white fly, slugs. Diseases: botrytis, stem rot. More on Calceolaria plants.

CHRYSANTHEMUM Soil: 1/2 soil, 1/4 sand, 1/4 peat or leafmold. Temp: 50° to 55°. Light: full light. Bloom Requirements: failure to flower may be due to too low a temperature or too long a day (light period); check the catalogs of specialists for recommendations. Insects: aphid, leaf nematode, thrip, midge, root nematode, mealy bug, white fly. Diseases: mildew, botrytis. Leaf spot may be troublesome; it is characterized by circular, dark brown areas on the leaf which eventually merge and become dry. Spray with captan. More on Chrysanthemum care.

CINERARIA Soil: 1/2 soil, 1/4 sand, 1/4 peat or leafmold. Temp: 50° to 55°. Light: full sun. Bloom Requirements: failure to flower due to temperatures above 600; requires 6 weeks below 60° for bud formation. Insects: spider mite, cyclamen mite, thrips, aphis, white fly, mealy bug. Diseases: virus; root and stem rot may cause sudden wilting; prevent by sterilizing soil and equipment.

CYCLAMEN Soil: 1/2 soil, 1/4 sand, leafmold. Temp: during the summer keep as cool as possible; during the winter grow 50° to 55°. Light: shade in summer Growth Problems: weak growth due to low light intensity or ex-cessive temperatures; dried leaf spots may be due to excessive light; bud blast due to high temperature or low light intensity. Insects: red spider mite, cycla-men mite, thrip, root nematode. Grubs eating roots may cause sudden wilting. Treat soil in advance of planting with lead arsenate at rate of 1 pound to 8 bushels of soil. Diseases: botrytis, stem rot.

FUCHSIA Soil: 1/4 each soil, sand, manure, and peat or leafmold. Temp: 50° to 55°. Light: protect from bright sun in early spring and summer Bloom Requirements: bud drop due to too dry an atmosphere. Insects: white fly, aphid, cyclamen mite, thrip, scale, mealy bug, red spider mite, slugs and snails. Diseases: botrytis.

HYDRANGEA Soil: for blue hydrangeas the soil should be treated with aluminum sulphate, 1 pound to 5 gallons of water applied at the rate of 1 cup per plant per week. This makes the soil very acid, 5.5 or lower. If difficulty has been experienced obtaining a good pink color, use hydrated lime at the rate of 1 level tablespoon per plant in early fall, about August, as if you wait until forcing time treatment may not be effective. Use basic soil mixture of 1/2 soil, 1/4 peat, 1/4 manure. Temp: 60°-65° after they have been brought in from the coldframe. Light: full sun, except light shade when in full flower. Bloom Requirements: failure to set buds due to (a) too high temperature – should have 6 weeks of temperature below 65′; (b) early frost which causes leaf drop before flower buds formed; (c) pruning after bud formation, thus removing buds. Insects: aphid, thrip, red spider mite, root nematode. Diseases: mildew botrytis. More on Blue Hydrangea

POINSETTIA Soil: 1/4 each of soil, sand, manure, and peat or leafmold. Temp: 60° to 65°. Light: full sun. Growth Problems: leaf drop usually due to allowing the soil to become dry for short periods; blindness occurs when night temperatures are above 65° or when days are too long (even an electric light near the plants turned on for a few minutes at night can cause blindness). Insects: mealy bugs, scale. Dis-eases: there are several troublesome stem rots and bacterial wilts; best control is prevention through sterilization of soil and equipment. More on Poinsettia care.

PRIMROSE (mostly Primula malacoides) Soil: 1/2 soil, 1/4 manure, 1/4 leafmold. Temp: 50°. Light: full sun. Growth Problems: yellowing and browning of leaf margins results when foliage suffers for water. Insects: aphid, thrip, white fly, red spider, mealy bug. Diseases: mosaic, botrytis, stem rot.

Part 1 | 2 in this 4 part series

by Charles H. Potter

Related Articles Of Interest:

• RX for Healthy House Plants-Part-2
• RX for Healthy House Plants – Part 4
• Spider Mites on Houseplants – How Can You Tell?
• 4-Point Summary of Plant Disorders