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How To Start Your Garden from Seeds: 2020 Iowa Seed Starting Guide

It’s still pretty chilly outside here in the Midwest, and we’re feeing a little antsy about getting back into the garden. It’s not quite time to start planting yet, but it is the perfect time to start thinking about planning your summer vegetable garden. While we have a pretty long growing season here in Des Moines at about 175 days, some things need a little longer to mature. We can get a jump on the season by starting some of our seeds indoors this spring.

Here’s our guide to starting seeds in Iowa.

What You Need to Start Seeds Indoors

Starting seeds indoors is fairly simple, but it’ll go a lot better if you have a few specific items that make the planting process easier. Here are the items you’ll need to get the best results possible when starting seeds indoors.

  • Starter soil mix
  • Starter containers
  • Plastic plant trays (with clear covers)
  • Grow lights (minimum of one 2′ light per tray of seeds, but two is even better!)
  • High-quality seeds
  • Labels
  • Seedling starter heating mat

Why Use a Grow Light?

We consider grow lights a seed starting essential because even in the brightest window, most seedlings will grow tall, leggy, and weak without supplemental grow lights. Many grow lights these days are LEDs, so they use hardly any energy, and the bulbs won’t burn out for years and years to come.

Grow lights need to be very close to the trays when plants are just sprouting, no more than 4 inches above the soil. This is to ensure the plants get enough light and don’t get too tall and spindly. As your seedlings grow, you can move the lights up, always keeping them around 3-4 inches from the tops of the plants. To make sure seedlings get enough light, keep grow lights on for 12-14 hours per day.

Using Heating Mats

Seedling starter heating mats are nice to have, but they’re not necessarily essential. You’ll have the most success with seed germination if you keep the soil temperature between 70-75°F. A heat mat makes it easy to maintain this temperature for your seedlings if the temperature in your house tends to fluctuate. 

Labels are essential, believe us! If you don’t put labels on your seedlings, the chances are that you’ll forget what you planted in each tray after a week or two. We have a few different options for planting labels that you can write the names on, or if you’ve got popsicle sticks left over from a child’s school project, you could use them.

When To Start Different Vegetables and Herbs

Many seed packets include information about when to plant the seeds indoors. Usually, they mention the number of weeks before the last frost date. Our last frost in Iowa is generally around the middle of April, so count backward from April 15 to determine when you should start planting each of your seeds indoors. 

January
January is a little too early for starting most seeds. There are a few woody herbs that are slow growers, like oreganolavenderrosemarythyme, and sage, that you can start in January if you like. 

February
Towards the end of February, you should be planting seeds for bell pepperscabbageceleryeggplantleeksonions, and tomatoes.

March
About the middle of March, you can start planting seeds for broccoliBrussels sproutscauliflowercollardscucumbers, and Swiss chard.

Towards the end of March, you can start planting seeds for cantaloupewatermelonlettucepumpkinssquashes, and sweet potatoes.

April
By mid-April, you should be able to start transplanting your seedlings outdoors, and direct seeding others into the garden.

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It might be too early to start sowing now, but it is a great time to do some research about any new vegetables and herbs you want to try this year. If you have trays and seedling containers you’re reusing this year, make sure to wash them up and rinse them with a water and bleach solution. If you already have grow lights, check to make sure the bulbs are all working. If you need to stock up or replace any equipment, visit our garden center in Des Moines! We can get you any seed starting supplies you need, as well as plenty of exciting seeds to inspire your planning.