I have planted them in 10 litre pots. They are outside since middle of February. what can be the problem.
Have you had cold weather?
It sounds to me cold damage, that they may have been exposed to a freeze.
Over watering without proper drainage would also be a concern.
Here is a link about the proper care of shallots.
https://www.gardeningknowhow.com/edible/vegetables/shallot/planting-shallot-sets.htm
My shallots have gone soft after the cold weather. Will they recover or do I start again?
Most likely the shallots will not recover from being frozen.
I would recommend removing and starting over. I have suffered this issue in past years myself with late spring cold.
https://www.gardeningknowhow.com/edible/vegetables/shallot/tips-for-growing-shallots.htm
NZ calling...I had a fantastic crop of shallots this past season with 2 different varieties and no sign of any diseases. I am keen to plant into the same bed again. Do you see any issues?
It is recommended to crop rotate your shallots planting location each year.
I personally have planted them in the same bed without any issues. I do add a fair amount of compost each each to the raised beds before planting.
Here is a link to shallot growing and care requirements.
https://www.gardeningknowhow.com/edible/vegetables/shallot/tips-for-growing-shallots.htm
Will bulbs form or will they just go to seed? I missed harvesting a cluster of shallots last year. This spring they look like a large clump of chives. I cut most of the flowers and the green looks very healthy but VERY crowded. Thanks for your time.
They should have formed clusters or bulbs, much like a garlic bulb.
There are good images on the links below.
https://www.gardeningknowhow.com/edible/vegetables/shallot/tips-for-growing-shallots.htm
https://www.gardeningknowhow.com/edible/vegetables/shallot/harvest-a-shallot-plant.htm
How to grow and harvest bulb shallots.
Here are some articles to help you!
https://www.gardeningknowhow.com/edible/vegetables/shallot/tips-for-growing-shallots.htm
https://www.gardeningknowhow.com/edible/vegetables/shallot/planting-shallot-sets.htm
https://www.gardeningknowhow.com/edible/vegetables/shallot/harvest-a-shallot-plant.htm
When will they be ready if planted in September last year?
They should only take around 90 days to mature. When many of the leaves are starting to shrivel. This article will give you more information: https://www.gardeningknowhow.com/edible/vegetables/shallot/harvest-a-shallot-plant.htm
This article (https://www.gardeningknowhow.com/edible/vegetables/shallot/planting-shallot-sets.htm) says plant the bulbs 1 inch deep. Is this the depth from the topof the bulb or the bottom of the bulb?