Sunday, December 9, 2012

Vegetable Container Gardens - Growing Sweet Corn

I have often had the pleasure of teaching Container Garden classes across the Chicago area. Frequently I'm asked specifically about growing vegetables.  I too am a fan of fresh home-grown produce!  I just received my first seed catalog and I've already started planning for next year...I'm planing corn but not in rows. :) Planning what to grow and where is a key activity in a gardener's spring garden to-do list. BTW, here's my running spring garden check-list


Sweet Corn fresh from the garden
Families with children can use this as a great teaching moment. Kids get excited about growing edible plants. When my kids were younger they liked planting seeds, seeing them sprout, and watching plants and fruits/vegetables grow. It's even more fun when they recognize the seed as well as the edible result. 


Corn is one of the oldest and most hybridized edible plants. Corn as we know it today is the result of generations of careful cultivation.  For gardeners that means many choices - maybe too many. I look for something sweet or decorative/color and is a dwarf variety which will grow easier in a small space.

VARIETY:  Most seed companies offer dwarf corn varieties for container growing. I like to look for early varieties, and those under 6 ft tall. Yield is highly variable - bee sure to pick a variety that yields more than one ear per plant. This also helps with self pollination. Best results will come with more than 6-8 plants, planted densely. A larger grouping ensures complete pollination.  A few to consider, space saving varieties, Golden Bantam, Kandy Korn, Precocious, Strawberry popcorn, Early Sunglow, Trinity, Casino, Sugar Pearl, Tom Thumb Popcorn, On-The-Deck Sweet Corn 
CONTAINER: Corn roots typically have an effective depth of 12 inches, although in the field some roots can reach 2 feet deep. So in container gardens corn doesn't need a particularly large pot - a 24" container should be sufficient.  I like to use the half a wine barrel or tub as well! Gives a bigger harvest and has needed weight. A key consideration is the resulting height of the plants - a 4 - 7 Ft dwarf corn plant will be 5 - 9 Ft. high in the container.  It's a great accent piece and very architectural!  Yet think about container placement as well as wind protection!
CULTIVATION:   For corn, use standard potting soil and make sure to add lots of slow release fertilizer. Plant corn seeds about 4 inches apart, covering them with 1 inch of soil. When the sprouts are ~6 inches tall, thin to about eight inches apart.  Then on, make sure the corn has a good supply of food and water. Never let it completely dry out. Provide fertilizer once a week or bi-weekly. When the plants tassel, help them pollinate by gently shaking the stalks or hand pollinate if you have multiple varieties and then detassle the corn to prevent cross pollination.
WIND PROTECTION:  I've heard of three options for protecting corn, tall flowers and bulbs from bending over in high winds.  I've tried mounding and rebar options with good success.  If your corn does get knocked down, and if the stalks are sound - just prop it back up, pack the soil around it, and it should keep growing.
You don't need a field to enjoy sweet corn fresh!
  1. WEIGHT:  Add stones and other weight to the container to keep the container itself from blowing over (this will not stop the plant from blowing over however)
  2. MOUNDING: Just bank up some dirt around the bottom of the corn when it gets about 8 inches tall. Cover it about half way up the stalk. This will help keep the corn stable, grow a stronger root system and will "feed" the plant more nutrients. It can be challenging in a container, you may try pulling a fabric over the container (similar to the nylon mentioned in rebar) to keep the soil mounded.
  3. REBAR - This works best for raised beds, but could be modified for container groupings. Get 1/2" rebar that is about 4 ft long (longer for taller varieties). Pound rebar in each corner of your garden area (or edges of the container, works well with wine barrels) Plant the corn.  After it sprouts but before it gains real height, take nylon netting (Home Depot or Lowes) and stretch it tightly across the rebar. Position the nylon at 1.5'ft.and at  3' level (1/3 and 2/3 your corn height). The corn will grow through the netting. The rebar and netting provide support to prevent wind damage.

I'm now thinking about sweet corn with butter, corn bread, corn salad - and can't wait to get some fresh.  My grand father used to walk through the field and pull corn off the stalk and taste it raw! 

Save some seeds for the next year! Oh an if you are interested check out this blog post on growing herbs in containers.


Teresa Marie