When the sun shines, nothing hits the spot like a fresh chilled soup says our man in the kitchen.

Dreaming up a chilled soup for a lunch or dinner party isn't too difficult at this time of year, with so many great ingredients around – some of them maybe even growing in your own garden. It's crucial that chilled soups are fresh-tasting and have a bit of zing or they can be really quite dull. You can create all sorts of interesting combinations, and at this time of year I often take a flask of chilled soup out on my boat while I'm fishing. Chilled soups are also great for picnics, and for long car journeys when they make a much healthier snack than the stuff on offer at service stations.

Fragrant watermelon soup

Serves 4-6

This Thai/Vietnamese-influenced soup could be served as a starter or dessert; I love the combination of fruit and a bit of spice. Other melons would work just as well – or a selection – and if you can find seedless watermelons even better. Because of the size of watermelons you will have some left for breakfast.

1 small or half a large watermelon
3 sticks of lemon grass
10 kaffir lime leaves
30-40g root ginger
2 medium red chillies
2tbsp granulated sugar
A handful of Thai or normal basil leaves

Peel the watermelon, chop the rind into chunks and put it into a saucepan with the sugar, lime leaves and 1 litre of water, then gently bring to a simmer to make a stock syrup.

Roughly chop two sticks of lemon grass and add them to the mixture; trim and finely chop the third stick and put to one side. Peel the ginger and add the skin to the stock syrup, and roughly chop one of the chillies and add that too. Continue simmering the stock syrup for 20 minutes or until you have about 200-300ml left, then turn off the heat and leave to cool.

Meanwhile finely dice the ginger and chilli as small as you can and transfer it to a small saucepan with the retained lemongrass and about 200ml of the syrup, strained. Bring to the boil and simmer for 2-3 minutes and remove from the heat.

Strain the stock syrup through a fine-meshed sieve. Cut the melon into rough 2-3cm chunks and blend half of it with the stock syrup in a liquidiser until smooth. Mix the ginger, lemon grass and chilli mixture in the syrup with the blended melon. Place in a container in the freezer for about 45 minutes until it's ice cold and refrigerate the rest of the melon chunks.

To serve, arrange the chunks of melon in shallow soup/pasta bowls, pour the cold melon purée over so they are just showing and scatter the basil on top.

Tomato, cumin and coriander soup

Serves 4-6

As you may know, cumin is my all-time favourite spice – it works with all sorts of meats, fish and vegetables and, chilled in this Indian-influenced soup, it's a winner.

If you can get your hands on different colours and varieties of tomatoes for the garnish all the better.

2 red onions, peeled and finely chopped
1tbsp rapeseed oil
2tsp cumin seeds
2tsp ground cumin
500ml vegetable stock
500g ripe tomatoes
A handful of coriander leaves (reserve the stalks)
Salt and freshly ground black pepper

Gently cook the red onion, half the cumin seeds and ground cumin in the rapeseed oil for 2-3 minutes until soft then add the vegetable stock and bring to a simmer. Roughly chop two thirds of the tomatoes and add half to the soup, season and simmer for 15 minutes then remove from the heat and leave to cool.

Take the remaining tomatoes, squeeze out their seeds and cut the flesh into rough 1cm dice and put to one side. Once the soup is cold, blend in a liquidiser until smooth with the rest of the roughly chopped tomatoes and the coriander stalks, then strain into a clean container, season to taste and refrigerate until nice and cold. Alternatively, you can speed up the process by placing it in the freezer and giving it an occasional stir.

Toast the rest of the cumin seeds under a medium grill and roughly chop the coriander. To serve, mix the coriander and tomatoes with the soup and ladle into soup bowls then scatter the cumin seeds on top.

Cucumber and lovage soup with crispy haloumi

Serves 4

Cucumber consists mostly of water, so it needs gentle and brief cooking to help it blend smoothly and bring out the flavours and to help prevent it separating once it's blended and chilled. Don't be tempted to add more lovage as it will really overpower the soup

1 small leek, roughly chopped and washed
1tbsp rapeseed or olive oil
2tsp plain flour
2 cucumbers, halved lengthways, seeds removed and disgarded and the flesh roughly chopped (reserve a quarter of one for garnish)
600ml vegetable stock
Salt and freshly ground black pepper
6-8 lovage leaves

For the garnish

150g haloumi, cut into 1cm cubes
1tbsp olive oil

Gently cook the leek in the olive oil, in a covered pan, for 2-3 minutes until soft. Add the flour, stir well, then gradually add the vegetable stock, bring to the boil and simmer gently for 15 minutes. Add the cucumber and lovage leaves and remove from the heat. Blend in a liquidiser until very smooth. Strain through a medium-meshed sieve (a fine mesh will trap too many bits) into a bowl set over some iced water to cool it quickly and prevent discolouring. Season to taste. Meanwhile, finely dice the rest of the reserved cucumber as small as you can and stir into the soup.

Heat the olive oil in a heavy, preferably non-stick, pan and cook the haloumi on high for 2-3 minutes, turning as it's cooking until it's crisp, then drain on some kitchen paper.

To serve, pour the soup into large chilled soup bowls and scatter the haloumi on top

Bolting herb soup

Serves 4-6

If, like me, you have a herb and salad garden that gets a little out of control at times and your plants start bolting, don't panic. The occasional cut back will certainly encourage growth and I like to serve the odd herb flower and bolting top in a salad or make a chilled soup like this.

Don't be tempted to use strong herbs or salads – thyme and lovage, for example, can kill a dish like this. But rocket tops and flowers are fine.

The tops from 2-3 spring onions or leeks or a handful of chive tops
1tbsp rapeseed oil
1tbsp flour
1.5 litres vegetable stock
Salt and freshly ground black pepper
2-3 large handfuls of herb and salad tops or the herbs themselves ( basil, chives, parsley, parcel, tarragon, salad tops etc)

Gently cook the spring onions, leeks or chives for 30 seconds or so in the vegetable oil. Add the flour and stir well, then gradually add the vegetable stock and any stalks from your herbs and season. Bring to the boil and simmer gently for 20 minutes. Add the bolted tops and/or herbs and simmer for 2 further minutes, and only then remove from the heat.

Blend until smooth in a liquidiser then strain through a medium strainer, as a fine- meshed sieve will not allow some of the bits of herbs through. To keep its green colour, you need to cool the soup down as quickly as possible, so put the bowl of strained soup over another bowl of iced water. Re-season if necessary and serve from the fridge.

If you feel like it, garnish with finely chopped herbs, crème fraîche or even fresh goat's cheese or curd.