Gardening Question of the Week: Summer Oil, Dormant Oil, Horticultural Oil.. Does it Matter?
Thursday May 15, 2008
I got this question while I was shopping for fertilizer the other day. Someone had read that she needed dormant oil for her apple tree and she wanted to know if she could still use it now, even though her tree was no longer dormant.
You don’t see dormant oil recommended much these days. The first dormant oils were heavy and you couldn’t safely use them on actively growing plants or you could damage the foliage. Dormant oils were further refined to produce lighter-weight oils that can be applied during the growing season, without harm to many plants. When the term dormant oil is used now, it generally refers to the application timing, during the dormant season, rather than a type of oil. Here’s the lowdown on what actually counts as a horticultural oil.
Photo: © Marie Iannotti (2008) licensed to About.com, Inc.
Comments
Marie – You are absolutely correct in your descriptions of and use recommendations for a dormant oil spray. Dormant oils used in season do carry a risk of leaf damage, especially to tender crops. We recommend that if you want to apply in-season you carefully and fully follow the label directions and that you apply on a cool(er)day.
Best
Don Allison
Bonide Products
All mentioned products plus Neem oil are quite effective against spider mites, insects, and scale early in the year. Problem – phototoxic – don’t use it on bright days especially in warm weather.