YouTube have some videos on how to repair cracked pottery, might be worth a look?

Thanks Shirley, will do. Hope you’re enjoying bank holiday weekend. 😉

Shirley, that's useful info. I have a big one with a chunk out of it. Not just a crack. I'll have a look at You Tube.

certainly a sealant will help hold it together but it wont withstand frosts. you could use a grout on the inside as it is ceramic like kitchen tiles.

Instructables is a good DIY site too.
Gorilla glue would work I should think.
Merlin, I've seen broken pots tipped at 45° or so & planted with trailing, ground cover like lobelia that spills out over the break & looks very effective

Amsterdam, lots of helpful suggestions there! Stayed home today as the traffic on a Bank Holiday Sunday around here is far too busy. Our daughter drove over to visit and it took her an hour and twenty minutes instead of the usual forty five minutes ... crazy!

If it's a hairline crack, a windshield repair kit, a blow dryer, and a sunny day might do the job.
First, empty, wash, and thoroughly dry the pot. Take it indoors, preferably under an incandescent lamp. Lay the pot on its side with the crack up, and apply the repair fluid to the crack. Put on the plastic sheets, and gently heat with the blow dryer to drive the fluid into the crack. Then take the pot out into the sun to set up the fluid. Remove the plastic sheets, and scrape off the excess glue with a razor blade. It works best on glazed stoneware: glazed earthenware often absorbs the fluid too quickly. That glue kit with the blue light may also work, but the glue there is usually too viscous to get into really narrow cracks.

Some good ideas for cracks Amsterdam.
Darren, I've filled it with bamboo which I will probably never be able to get out because of the shape. Yes I like the idea of sideways pots and have a couple that I could do that with.

It's best with your favourite ceramic containers to use plastic pots inside, the moist soil freezing & expanding is likely to cause cracking.
I've got a metal watering can that wobbles about on the ground because the water in it froze & bowed out the base