Have you wanted to start some spring and summer plants from seed, but don’t know the best time to start them?
Perhaps you tend to start “late” and then your seedlings are tiny when it is time to plant them in your garden and you go out and buy plants anyway.
Whether either of these are you, or you simply want a simple formula to start your seedlings, this post is for you.
Know when to start your seedlings
On most seed packets you will find some useful information.
Recently I came across someone’s post who said they never read the seed packets and just wing it. They also lamented that their seedlings weren’t ready when they wanted to put in the in the ground.
The simple solution is to read the seed packets and follow this formula.
It has four parts.
- Days to Germination
- Days to Maturity
- Planting Time
- Last Frost Date
Let’s start by defining a couple of terms.
Days to Germination
You’ll see this on the seed packets, sometimes listed as “days to sprout” or “days to emerge”.
This will be a number and is the average number of days from the day you plant the seed, you can expect to see the seedling come up.
Various factors play a part in how close to that number of days your seedlings sprout.
For example, older seeds tend to take longer to sprout.
Some seeds prefer warmer temperatures, some cooler. Some need light to germinate, and therefore should not be covered, some want darkness to germinate. These are the things you learn by reading your seed packets.
Days to Maturity
You might also see this listed as “days to harvest” or it might simply say “days”.
This means the average number of days from the time the seedling sprouts to when you can expect to harvest it, or for it to bloom.
Again, climatic factors can modify when your tomato plant is pumping out tomatoes, or your zinnias are blooming.
Planting Time
Planting time depends on a couple of factors. First, if the plant likes it warm or cool.
Spring crops that like it cool will want more cool days in your garden to mature, where as your summer crops may not want to get planted in until cold weather has passed (more on that a bit).
The Seed Starting Timing Formula
The formula is calculated like this.
Pick the planting time, then calculate backwards, the Days to Maturity, then the Days to Germinate.
In the real world, you will do these in reverse order. 1, 2, then 3.
Last Frost Date
To choose when you put your seedlings in your garden, we use the last frost date for your area. This means the last average date you can expect you won’t get frost for the summer.
This date is calculated in the US by the USDA Planting Zones. They update the zones and dates every four years.
You can put in your zip code on their website and it will tell you your planting zone and your last and first frost dates. (Your first frost will be in your autumn.)
So that is it! A simple formula, based on when your seedlings want to be planted.