Certain varieties of beetroot, cauliflower and broccoli can be sown undercover in modules. Multi-sown beetroot can be planted out as they grow (without thinning), allowing you to harvest smaller roots while leaving others to grow. Brassicas can be potted on when they are big enough, preventing pigeons and slugs from eating them when they are small.
I like to use the following for early sowing;
Cauliflower - 'All the Year Round'
Broccoli - 'Ironman'
To chit, or not to chit, that is the question!
I personally chit my seed potatoes by standing them up in wooden trays or old egg boxes in a frost-free shed. By doing this, the tubers produce small growing tips from the eyes; these will produce the plants foliage when they get planted out. No matter if you chit your tubers or not, its always best to get them out of the bag they are delivered in (especially if its a netting bag), as emerging shoots can get caught in the netting and be damaged when you open the bag.
Towards the end of the month I like to weed my over-wintered onions, garlic and shallots. You'll be surprised at how many annual weeds can start to grow in January if it's a mild year, plus it's a good time to dig out any perennial weeds which are making themselves known. After weeding I like to sprinkle dried chicken manure around the plants and gently hoe it in to give the plants a boost as they start to grow. Alternatively, you can feed plants a nitrogen-rich fertiliser, such as sulphate of ammonia, at around 35g per square meter.
Lettuce plants are hardier than most people think, perfect to get sowing and growing in an unheated greenhouse now. I sow a pinch in a seed tray or seed pan every couple of weeks from mid January (as long as the compost isn't frozen) and they will slowly start to germinate in the winter sun. You can use your plants as cut-and-come-again lettuce once they are 10-15cm tall or you can prick them out and grow them on as loose leaf plants, perfect for salads and sandwiches. I like to use older seed which was opened last year for this task, as you only need a few pinches.
Greenhouse plants which need a long growing season, such as chillies and aubergines, should be sown this month if you have a heated propagator. Seedlings should be kept warm with as much light as possible, so consider buying a small grow light or using tinfoil at the back of your propagator to reflect light back to the seedlings. It's also a good idea to turn the plants every day so they don't begin to lean towards the light. Note: If you don't have the equipment, wait until late February to sow on your kitchen windowsill.
Rhubarb, sea kale and chicory can all be forced at this time of year to produce sweeter, milder, more tender stalks and leaves. Covering the plants with an old forcer, black bin or old pot (as long as the light can't get in) is an easy way to encourage your plants to produce these gourmet treats. Rhubarb will produce pale pink, sweeter stems which are delicious in pies and crumbles, but also make a gorgeous jam. Sea kale is favourite of the Victorian era and produces a tender stem vegetable which is lovely steamed, while chicory is far less bitter when forced.
As a general rule, the hotter the chilli, the longer it takes to grow and ripen; therefore its best to get any super-hot ones sown this month in a propagator with heat and grow lights. Unless you are a real "chilli-head" you won't need that many plants as they produce lots of fruit, so don't sow too many seeds or it will get too hot to handle!