Swiss chard is not a perennial, it is actually a biennial which means it lives for two years. It can survive over winter and then flower and set seed in its second year before dying off.
So What Does This Mean For You, The Gardener?
This means that you can grow swiss chard for a large part of the year, you can sow it in spring grow it all year, overwinter it and then it will still be growing the following spring.
When summer comes around, it will start to go to seed; at this point, you will need to dig it up as it will start to taste evermore bitter.
So when the plant is in its second spring I would be sowing some new seeds do you have fresh plants ready to replace the old ones come summer.
Overwintering Swiss Chard
Swiss chard can tolerate temperatures down to around -10 degrees celsius, so for most UK winters, you should be just fine to leave it alone in the garden.
If a period of extreme cold is expected then you could use some fleece to add a bit of extra protection to the plant.
Your swiss chard won’t do any growing over winter so you won’t be able to harvest any leaves off it but it will survive and then start growing again in spring.
You can normally start harvesting the fresh growth around march time although it obviously depends on the weather conditions that year.
How To Cover Swiss Chard
Swiss chard growing outside in your garden beds can need a little protection on really cold nights, to do this you can just use some fleece.
Don’t just dangle some fleece over your swiss chard because this can sometimes do more harm than good. That is because if the fleece ever touches your swiss chard it can cause burning to the part of the plant it touches.
So to use garden fleece correctly you also need to have some sort of frame to keep it up and away from the plants leaves.
This frame needs to be strong so it can hold up to the weight of some snow piling up on the fleece.
How To Grow Swiss Chard From Seed
If sowing in early spring you are better sowing in modules in a greenhouse just to get growth going a bit quicker. If you are later into the season then you can sow them directly to the ground in shallow drills.
Plant the seeds roughly 1 to 1.5cm deep. Use multipurpose compost or seed compost, whichever you have available.
After a few weeks you will be able to plant them out, plating in rows is the most common method and keep your rows about 30cm apart and plants 20cm apart.