Guidelines for Planting Vegetables in Springtime

Spring Vegetable Planting

Tom Ingram: Ask a Master Gardener

Sunday, March 04, 2018

Q: When can I start my vegetable garden? MA

A: Oftentimes, people will suggest certain dates when you can plant your vegetable garden. But dates are only guidelines. To know for sure when you can plant, we must look at the weather and do a little investigation to determine soil temperature.

For example, oftentimes people will say St. Patrick’s Day is when to plant potatoes. There is no potato magic in St. Patrick’s Day, other than in a normal year you are probably OK planting on this day. The truth about when to plant is based on the best soil temperature for planting potatoes.

According to the OSU Extension, soil temps need to be above 50 degrees before we plant potatoes. At the writing of this article, soil temps are hovering around 46 degrees. So, we are getting close, and if the weather continues on as we expect, we will likely have a soil temp above 50 degrees by St. Patrick’s Day. But give us a few warm days and an expectation that spring is on the way and we could plant them sooner.

Peppers are easy to grow in Oklahoma and have the benefit of being a versatile crop. However, peppers are sensitive to temperature. Air temperatures of below 60 degrees or above 90 degrees can prevent fruit set, which can limit the growing window in Oklahoma.

So, how do Oklahoma gardeners get around this? Because cold soils do not encourage germination, it is common for gardeners to start seeds indoors so they will be ready to go when it warms up.

If you have been to any of the garden centers in northeast Oklahoma recently, you will have noticed racks of seeds and seed-starting supplies. Many of us have already gotten our seeds started and can’t wait to get these little ones in the ground.

But the time to plant these transplants still depends on soil temperature and when the danger of a freeze has passed. In northeast Oklahoma, we typically say that date is April 15. Many of us have a hard time waiting that long and tend to plant before that date. However, if you do, you should be ready to cover your plants if a late-season snow arrives.

Now, you may be saying, all this talk about soil temperature, how am I supposed to know that? In Oklahoma, we have a wonderful resource called the Mesonet. The Mesonet is a joint project between OU and OSU with at least one weather-monitoring station in each county.

You can visit mesonet.org for an abundance of weather information, including rainfall and soil temperatures. We also have an abundance of resources on our website to help you grow better vegetables.

Garden tips

• Our yearly Urban Gardener classes begin March 15. Topics include plant botany, soil, growing fruits and vegetables, flowers, trees and shrubs, and turf.
• We will also be conducting our educational Lunch & Learn classes at the Tulsa Central Library downtown beginning March 20.
• One of our most anticipated events is currently underway: The Master Gardener Plant Sale. You can choose from 211 plants including annuals, perennials, grasses, herbs and tomatoes.
• To sign up or find out more information on any of these programs, visit our website, tulsamastergardeners.org.