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Seeding Petunias
by Barb Foster
by Barb Foster


Inspired to nuture, Barb Foster took up gardening over a decade ago. She has a particular passion for this areas hardy perennials.

Barb collects her own seeds, grows seedlings in a greenhouse and has 500 sq ft of growing beds plus numerous perennial flower beds in her Zone 1b garden in Chetwynd, B.C.

Barb writes weekly for the Chetwynd Echo.

February 10, 2013

Petunias need to be started indoors by mid-February. Most Petunias, require 10-14 weeks, from seeding, to bloom.

Use a pre-moistened, fine soil-less seed starting mix as a seed starting medium. Germinate at 80 degrees F/27 degrees C soil temperature. Use bottom heat if possible. Press seed to soil surface, do not cover seed as it needs light to germinate. For watering, use a very fine spray mist of tepid water or set the seeded tray into a shallow pan of tepid water, assure good drainage after watering. The very small seeds should not be disturbed. Cover the seeded medium with a sheet of glass or clear plastic. Support the plastic with wire hoops so that the plastic does not touch the seeded surface. The plastic/glass cover can cause an extreme build up of heat that could cook the seed or seedlings, so never allow direct sunlight on covered seed containers. After germination gradually uncover seedlings and during periods that the cover is removed gradually expose the seedlings to sunlight over a period of a week or so.

Grow seedlings at 50 degrees F/10 degrees C, in bright light for about 12 weeks. After two sets of leaves have developed fertilize, once a week, with 1/4 strength 20-20-20. Transplant to sterilized, humus-rich soil mix in well drained containers, after three sets of true leaves have grown. Space seedlings two or three inches apart, to allow room for growth, or transplant to individual three inch pots. Shade for a few days after transplanting to reduce transplant shock. But for the most part Petunias enjoy growing in full sunlight.

Towards mid-May, when out door temperatures rise above 50 degrees F/10 degrees C. (remember the wind-chill will lower temperatures), hardened-off container grown Petunias can be placed outdoors in sheltered semi-shade, for about an hour the first day. Then for longer periods each successive day, bringing them indoors at night, for a week or more. When there is no danger of night frost, the Petunias may be left out over night, for a few nights. On a cloudy day, or in the evening, the Petunias then may be planted out in the garden. Containers of Petunias, such as hanging baskets, could be potted up much earlier, and moved in, or outdoors, as the temperatures require (even after hardening off the temperature should always remain above 5 degrees C minimum). Protect Petunias from wind and heavy rain. The Petunias will continue to bloom until the frost kills them.

Petunias growing in the garden need a ring of ashes, bran, or crushed egg shell around them, to help protect them from slugs. Cut back leggy growth for a more compact plant. Remove finished blooms. Fertilize and water regularly.

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