How to Use Cornstarch to Perfectly Germinate Carrot Seeds for Late-Summer Planting
If you forgot to plant carrots in the spring, don't stress just yet. You can actually plant some for a fall harvest as well, up to 10 weeks before your climate's first fall frost, which you can check via the Old Farmer's Almanac.
According to the Old Farmer's Almanac, carrot seeds germinate "after the soil temperature is at least 40°F and germinate best at 55° to 65°F, not exceeding 75°F."
This means that high summer temperatures are less than ideal for this orange vegetable, as they cause reduced growth and a bitter flavor. Which means that a mid- to late-summer planting - now or within a few weeks - may be your best option for a great harvest.
And to increase the odds of a bountiful harvest, creators Jamie Walton and Martha Swales shared a way to use cornstarch to perfectly germinate carrot seeds, retain water and withstand expected high temperatures.
The hack, recreated by British gardener and content creator Maddie, aka @maddieinthemaking, shows how to do it at home with simple ingredients and a few easy steps.
@maddieinthemaking I think this may be a genuine hack for sowing carrot seeds I found myself panicking recently because I still hadn't sown my carrot seeds and the weather is hotter then I'd like it to be when sowing them! Carrots are notoriously difficult to germinate when it there is dry and hot weather, and lots of people use planks or coverings to cover the area where carrot seeds are sown to retain moisture. Now I don't have any planks or anything that can go in my vegetable bed so when I saw this hack of using a mixture of water and cornflour, I knew I had to give it a go. It is 100% not my idea, I simply just saw it at the right time and decided I would try it out. I'm also using a particularly rare variety of carrot which is the Organic Manchester Table Carrot from @realseeds so ultimately germination success is huge here! The science behind this hack is that the cornflour and water gel acts as a way to retain water and stops the seeds from drying out too quickly and too early. Honestly, in my eyes anything that makes it easier for the carrots to germinate is a good thing! Thank you to @Nettles and Petals and @Martha for sharing this recently #gardening#growyourown#vegpatch#beginnergarden#gardenhack
original sound - maddieinthemaking
Materials Needed to Germinate Carrot Seeds
To get started, simply gather:
- Water
- Cornstarch
- Small pot
- Carrot seeds
- A piping or Ziploc bag (not necessary, but makes the process easier)
Before getting started, also make sure you have a garden bed or area where you will sow and plant your carrot seeds.
Related: Gardener Shares Easy Step-by-Step Method for Growing Perfect Carrots From Seed
How to Sow the Seed Mixture in Your Garden Bed
Combine your cornstarch and water into a pot and cook slowly over low heat. You will likely need one to two tablespoons of cornstarch per cup of water you plan to use. However, you want to keep some extra water and cornstarch close by, just in case the mixture becomes too watery or too thick. You're aiming for a gel-like consistency.
Once fully cooled, mix in your carrot seeds and put the mixture into a piping bag, or fill a Ziploc bag and cut one of the corners off.
Then, create rows a few inches apart where you want to grow your carrots, and pipe the seed mixture directly into the lines. Cover them with dirt and water as usual.
While Maddie is not able to share her results quite yet, those in the comment section have confirmed using the idea before and its success.
"My parents used to do this every year when I was a little kid and it always worked wonderfully! These days, they don't eat carrots so this trick isn't in use but still a 10/10 'hack,'" wrote one commenter.
While you may still have to wait a little while before putting this germinating technique to work, it is a perfect and easy one to keep in the back of your mind for planting season this summer or next spring.
Related: Gardening Expert Reveals a Stunning 'Pretty in Pink' Garden Scheme Anyone Can Recreate
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This story was originally published July 13, 2026 at 2:30 PM.