Can I plant Morning Glory at any time (in USDA Zone 10)?

Question

It's late Jan now. I want to plant a climbing vine on my second-floor, east-facing, balcony railing to give a little shade in the morning. Come Spring and all through to the Fall, that morning sun shines through the balcony windows and turns my apartment into an oven. I'm cooked well-done before noontime. I live just a few miles South of Los Angeles, Zone 10? I'm wondering if I can get a jump on growing this thing in Feb before I start sweating it out in the Spring? I thought that I should ask before I start stringing wire to the rafters or buying/making planters. I'm quite ignorant of gardening stuff. My mom and dad would be kinda disappointed.

Answer 1

Morning glory seed will rot in the ground if the soil is not warm enough. They are sullen when it's cool. Grow them in a container with soil that stays warm, until the ground is warm. They are heat-loving.

Answer 2

Your USDA Zone represents the minimum annual temperature -- useful for predicting whether a given perennial plant will survive the winter. If you're in Zone 10, that means your expected minimum temperature is about 30°F (35, if you're in 10b)

If you're planting an annual morning glory like Ipomoea purpurea, then your frost-free dates will be more helpful than the USDA Zone. See, for example, best planting dates for Anaheim, CA. That chart doesn't list morning glory, but morning glory does well in hot weather so you could use planting dates for other heat-loving annuals like melons or tomatoes as a proxy.

This page discusses starting morning glory from seed. So based on the chart above (frost-free after March 1) and the germination temperature of 75-80°F, you should:

1. Start the seeds inside now, keeping the soil warm during germination.
2. Transplant outside (or move the containers) in about six weeks (which would be March 5; any time after March 1 should be fine).

Note that the Weekend Gardener page linked above says:

scarify seeds by nicking them with a file, then soaking them overnight in lukewarm water

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I used 92801 (Anaheim) as a rough guess, substitute your ZIP code in a chart like the Old Farmers' Almanac or check your city in Victory Seed's chart. If you know that your location gets colder than surrounding areas, then transplant outside a little later, or plan to move the containers back inside if you're expecting cold temps overnight.