He had me at polenta.

You know — that creamy corn goodness that foodies love to cook up for potluck parties? (Yeah, I’ve never made it, either.)

Last month I was chatting with Chad Borseth of Native Seeds/SEARCH about what corn to select for monsoon planting, and he recommended a popcorn variety that’s also delicious for polenta. Plus, the kernels are a pretty blue-green color. Sold!

If you’ve lived in Tucson long enough, you’ve probably heard of the Three Sisters concept. Native peoples — across North America, not just here in the Southwest — would plant corn, beans and squash together.

The beans climb the corn and provide a boost of nitrogen, and the squash shades the roots, squeezes out weeds and lowers water loss caused by evaporation.

In Southern Arizona, the trio is planted in time to take advantage of the monsoon rains.

I’ve never grown corn before because of space issues — it’s wind pollinated, so you need to plant enough to promote pollination. But I was tempted to give it a try after reading about the heirloom and native corns that thrive here.

Also, in my new-to-me 1950s-era home, I have a filled-in pool in the backyard that is begging to be planted with something dramatic yet useful.

All I need to do is install a simple drip irrigation system, dig in some compost, manure and amendments, and I’m good to go.

What I’m planting

At Native Seeds/SEARCH, I chose two varieties.

1. Glass Gem popcorn. $7.95 for 50 seeds.

This corn produces mature ears of beautiful colors. It’s best for popcorn or ground into polenta. It can be eaten off the cob, but you have to catch it at the “milk stage” before it turns color.How to plant: Plant 1 inch deep in blocks. Harvest when husks have dried, about 110 days after planting.

2. Stowell’s Evergreen sweet corn: $4.95 for 100 seeds, which should be enough for two seasons. This is an heirloom corn that does well in Tucson and is great eaten on the cob, Borseth says.How to plant: Plant 1 inch deep in clumps or basins. Ears are 10 inches on 7-foot stalks. Needs rich soil and moisture, and matures in 90-plus days.

Timing is everything

There’s a trick to the Three Sisters planting method, as Borseth explains. It’s all in the timing.

Time the pollination for when the summer heat has eased a bit, so late August is the target. Count back 30 to 40 days from then, so that means waiting until the second or third week of July to plant the corn.

With the monsoon off to a good start, I’ll start planting this weekend, July 12-13.

Chad Borseth’s tips

Step 1: Amend the soil well with composted goat, horse or sheep manure and compost. Corn is a heavy nitrogen feeder, although the beans act as nitrogen-fixers and won’t compete for nutrients. If you’ve done a good job of amending the soil, you shouldn’t need to feed in the middle of the growing season. But if you do need to fertilize, use fish emulsion and water it in.

Step 2: Plant the corn close together in mounds or clumps, not in rows. Because corn is wind pollinated, it does better planted three to five kernels together, while leaving a 6- to 12-inch space, then planting another three to five kernels. Since I’m planting squash, I’ll make it a foot or so between corn mounds. I’m planning to follow a spiral shape inside the old pool area, with space inside for a chair or two.

Step 3: Start with the corn first and give it a 10- to 20-day head start. It should reach about 6-8 inches.

Step 4: Plant the beans right next to the corn, on either side, and plant the squash in the middle gaps.

Step 5: Water every day, especially as the corn gets established. Use drip irrigation and water slowly and deeply through the root zone.

Other tips
  • Cross-pollination: Planting two corn varieties together is fine as it won’t change the taste. But if you plan to save any of the seeds, they will be affected by cross-pollination. Stagger planting times if you want to save the seeds.
  • Mulch: Use a good, thick mulch, such as alfalfa hay or mesquite leaves.
Other plants
  • Green beans: I chose Blue Lake FMIK. I’ve found that beans like a little heat but not when it’s brutal. I’ve gotten late spring and fall crops, but while they can survive the summer, they refuse to flower during the hottest months, at least in my experience. I prefer bush beans to pole beans for their tenderness and mild flavor.
  • Spaghetti squash: Any winter squash will do — choose what you like to eat, Borseth says. I love spaghetti squash and have yet to try growing it. Immature spaghetti squash can be eaten like a summer squash, he says. The mature version — with its hard skin and brown stem — is similar to what you’d find in the supermarket.
  • Acorn squash is another good choice, and I will plant some of that, too.