Congratulations on catching spring fever and ordering your garden seeds!  Okay, so what comes next?  If this is your first time starting garden plants from seed, relax, I’ll walk you through the process.  Here are five steps you need to take to prepare your garden seeds for planting.

  1. Determine when you need to plant your seeds by reading the back of the seed packet. Some seeds, like onion, broccoli, and pepper, should be seeded indoors in the winter months while others like pea, lettuce, and radish are best direct seeded in the garden in early spring.  Here’s how you determine when to seed.  First, figure out the date of the average last frost for your area.  We covered this topic in the recent blog post ‘Days to Harvest Demystified’.  Second, read the back of the seed packet for planting recommendations.  Let’s follow an example: 

Packman Hybrid Broccoli seed (days to maturity 50-70 days), start seeds indoors or direct sow in garden. 

starting broccoli from seed

Okay, so I choose broccoli because it is a tricky one.  One thing about broccoli is that it grows best and produces the best heads when temperatures do not exceed 75°F, but is seriously damaged at temperatures below 30°F.  Multiple areas throughout Utah, including the Salt Lake area, do not enjoy a long mild spring every year so we might not experience too many weeks of temperatures in this range (temperatures may transition from very cool to hot in just a few weeks’ time).  Packman Hybrid broccoli plants require 50 to 70 days (7 to 10 weeks) of temperatures between 30 and 75°F to form heads.  In other words, depending on the year, you might or might not enjoy broccoli heads if you direct sow seeds in your garden.  So for broccoli, I would suggest starting seeds indoors (5-6 weeks before the expected planting date) and transplanting starts outdoors 2-3 weeks before average last frost.  Okay, so if my average last frost for Salt Lake City is April 13th, I want to plant transplants outdoors the end of March, so I want to start my broccoli seeds indoors the last week of February.  I know it seems early, but for some vegetables, it is essential to plan ahead!

  1. I know I may have thrown you a little with all the detailed information on temperature extremes and weeks before planting. How were you supposed to know that, right?  tomatoes in the garden factsheetRest assured, you weren’t, but you should know where to go to find it! I got all this information from vegetable fact sheets on the USU Extension website.  Go to, select ‘gardening’ in the top selection panel, and then ‘yard and garden’. Once you get to that page, you will see ‘fruits and nuts’ and ‘vegetables and herbs’ on the left side selection panel. Once you click on ‘vegetables and herbs’ you will see a list of choices.  I chose ‘broccoli’ and clicked the option ‘for more information on broccoli, click here’.  This took me to the full fact sheet on growing broccoli in Utah. These fact sheets are fantastic; it’s like have a recipe for growing garden plants – each with specific information on planting, fertilizing, irrigating, harvesting, pest control, and variety suggestions.  Talk about making it easy!Plastic Domes for Seed Starting
  2. Once you know your average last frost date and you determine when you need to plant your seeds, it is helpful to get it all written down in one calendar. So back to the broccoli example, I would want to mark ‘start broccoli seeds indoors’ the last week of February, and ‘transplant broccoli starts outdoors’ the last week of March.  I can even mark ‘watch for broccoli head development’ between mid-May to mid-June (50 to 70 days after moving transplants to the garden).  While you are at it, go ahead and mark the timing of other care requirements like fertilization (apply ½ cup per 10 foot row of nitrogen fertilizer (21-0-0) 4 weeks after transplanting into garden or thinning direct sown seeds – apply an additional ¼ cup of nitrogen fertilizer (21-0-0) when broccoli head is the size of a quarter).  I found this information on the broccoli fact sheet, easy, right?  You can also input all these dates into your work calendar of set them as reminders on your smart phone.  That way, you don’t need to remember to check a calendar, you will have all the reminders you need sent to you electronically – how savvy! USU Extension Calendar
  3. Gather and purchase all the seed starting supplies you need to start seeds indoors. This includes a light table (either store bought or DIY at home).  USU has a great fact sheet that covers the essentials called ‘Grow Your Own Transplants at Home’

We will also cover seed starting extensively in upcoming blog posts so stay tuned. You might want to think about how much space you will need to start your seedlings and where you want to put them so a) they are not in the way but b) they are enough in the way that it will be convenient to check them daily.

  1. Although seed starting indoors is fun, it is also an expense and a fair bit of work. Read the fact sheets on vegetables and identify which garden plants you need to start by seed and which you can directly sow into the garden. Directly sowing garden seeds also requires work (seeding, watering, thinning), but in my opinion, it is less work than starting seeds indoors. Future blog posts will cover different types of vegetables and which should be started indoors and which can be directly seeded into the garden. Only take on what you think you can handle and what you have room for inside the house. You can always purchase vegetable starts from the garden center; family feuds should never start over vegetable plants!