When gardening, losses to pests can be reduced with proper production and pest control practices. If chemicals are used, follow the label instructions and pay attention to the pre-harvest interval (PHI) to determine when it's safe to harvest your vegetables.

Produced by the Department of Communications at Kansas State University. For more information, visit our website at: http://www.kansasgreenyards.org

Pesticides - When Can I Harvest?

When you find insects in your garden, and you’ve tried everything else, you may need to spray either an insecticide or a fungicide. One thing you need to think about is “how long do I need to wait from when I spray my product, until I can harvest the vegetables again?”

Some pesticides can be sprayed, let dry, and then it’s safe to pick your produce on the same day. With other pesticides, you should wait perhaps three or seven days before you pick your produce. The only way to know how long you have to wait is to read the label on the pesticide container very closely.

The label will have some key words. It may have a code called PHI, which means pre-harvest interval. If it says three day PHI, you’ll need to wait three days from when you spray until you can harvest. Or in other cases, it may just say “Days to Harvest – 7.”

As a home gardener, you may be thinking that “There’s a lot of produce that the plants have, and I’ll have to wait seven days. How can I avoid loosing all of the produce that becomes ripe?” The first thing that you can do is to pick everything off of the plant that is ripe, or will soon become ripe, before you spray.

The other thing that you can do is to look for a pesticide that has a shorter pre-harvest interval. Perhaps you’ll need to wait only one or two days between the time that you spray, and when you can harvest again – instead of four or seven days.

If you can’t find the plant on the label somewhere, then it means that it’s not safe to use on that plant. Always read and follow the label instructions whenever applying any fungicide or insecticide in your vegetable garden.

This feature story prepared with Rebecca McMahon, Kansas State University Research and Extension Horticulture Agent, Sedgwick County. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.

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