The seeds are quite small. I usually sow them when the soil gets warmer, outdoors or in the greenhouse. I'm going to let this batch germinate indoors since it's still cold outside. Learn more about how to grow string beans early below.

Do you have a greenhouse or a polytunnel in your garden? In that case, I have a great tip for you: Grow string beans early this year! I've been growing them in early spring since 2015 when I got my large polytunnel. The earliest string beans are the best of the season, in my opinion!

These beans are also called French beans, green beans or haricoverts.

Read more: How to store dried beans long-term

Sensitive to the Cold

It's not entirely easy to grow string beans this early, so you need to be aware of the risks. All kinds of beans (except the fava bean, which is technically not a bean but a pea) are very sensitive to cold temperatures. I live in zone 3, so I'm definitely going out on a limb here, growing them already in April/May. But what would life be without taking risks?

My guess is that you delay the sowing a bit longer if you live even further north than I do. April might be a better starting time than March? Either way, growing string beans early is a great way to kick off spring.

Just know that the string beans might need some type of protection inside the greenhouse too. A row cover or some type of plastic miniature greenhouse on top might just do the trick.

Read more: Planting and growing beans

I sow two seeds or beans in each pot when I grow string beans. This is a tip I got a long time ago from a friend of the family called Maria.

Growing String Beans in March

My garden is like I mentioned earlier in zone 3, and mid-March is the perfect time to start sowing. You might be able to get going even earlier than that though. It depends on where you live.

Today, I'm growing my favorite string bean variety called Nautica. It's a low-growing variety (these generally grow faster than the taller varieties) which quickly produces plenty of skinny little beans. I generally sow two beans in each plug or pot. This will help me get sturdier plants overall. I don't soak the seeds before I get started.

I did this year's sowing quite spontaneously when I was in the polytunnel, but you should of course leave your pots indoors to get the germination going. Beans need warm soil to germinate. At least 60 degrees (16 degrees Celsius) or similar. I keep mine in a window without a grow light in our laundry room right now.

All in all, I decided to put twelve seeds in six small pots.

More: Growing snow peas in a plug tray

I'm using regular store-bought soil for this sowing. I don't need to use a potting mix to grow string beans here.

Planting in April

Beans germinate and grow quickly when they like their setting. So, there's really no reason to sow them too soon. The risk of infestations might actually increase if you keep them inside too long. My rule of thumb is to do it in a way where I don't have to transplant them to new pots before I put them outside in the greenhouse.

Since beans like heat, I need to wait a while before I plant the beans in the greenhouse. It's a bit tricky! We can still get nights of frost here during spring, even if the next ten days are supposed to be frost-free. I'm just going to see what happens and not take it too seriously. After all, I only lost my plants to the cold one single time these past few years. I felt very unlucky at the time, but every batch since has been just fine.

What about frost?

I put the beans in one or more rows in the soil. The reason why I grow string beans right in the ground is that it's actually easier to protect the plants against frost here, rather than in pots on the shelves or similar. I also use row cover on top of the plants during cold nights, and possibly also add little plastic containers just to make sure.

You might want to put the beans in different areas of the greenhouse/polytunnel. Frost is so unpredictable. One area can be just fine while another one freezes.

The string beans are long and slender, and they come in different colors. For example green, yellow or purple. Yellow string beans are also called wax beans. I want to grow string beans in every color!

My first kidney bean harvest

My greenhouse string beans are usually ready in May. We get fewer plants in the greenhouse than if we grow them in the beds outside of course. But my philosophy is that early spring gardening is more about quality than quantity. And nothing gets me as excited for the growing season as a simple handful of homegrown vegetables in early spring.

Let me know if you try to grow string beans early and tell me how it went in the comment section below. Good luck!
/Sara Bäckmo