Spring is just around the corner, though as I write this the wind is howling and the rain is falling almost horizontally. But it is the start of spring sowing time and I am making a start in the greenhouse. I have perennials coming up, lettuce seedlings ready to plant in the polytunnel and the tomatoes are sown, slightly earlier than I usually start, and I need to get the peppers sown. But I need to make a start on outdoor sowings soon.
Parsnips are often the first seeds to be sown in spring because they need a long growing season. The problem is that they are often sown so early that they take ages to germinate, it is so cold. And this gives them a reputation for being slow to germinate or a poor germination rate. Most umbellifers, and in the veg garden that means parsley, carrots and parsnips, lose viability quickly after the packet is open so either store an opened pack in the fridge for later sowings or buy fresh seed every year. I opened a pack of parsley last year, sowed some, and kept the rest in the fridge and it has germinated well this spring.
But back to parsnips, a good option is to germinate them in heat first and then sow the seeds, already bursting with life and with tiny roots showing, in the garden. There are various ways you can do this but the simplest is to use a plastic container with a lid, put some kitchen paper in this, wet it so it is wet, not just damp, but not sitting in a puddle of water, and scatter seeds over this. Put the lid back and place it somewhere warm (above 15c). Keep an eye on them and lift the lid slightly, as you would when microwaving something, when you see the first signs of roots emerging. Then, before they get too long, you can plant these individually in rows in the garden.
The huge advantage of this, over regular sowing, is that you should be sure that every sprouted seed will grow so you can space them quite evenly and there should not be much thinning needed. You can’t really do this with carrots because the seeds are so small.
Carrots need to be sown direct in the ground and you should never sow them and transplant them because the roots will be weird shapes and the plants will be more likely to bolt. In the same way, never buy pots of carrot seedlings to plant out. Some people, allegedly, sow carrots in the greenhouse in guttering and slip the compost and seedlings into trenches in the soil later but this seems like an awful faff and I am not very convinced it will work unless you grow short carrots. But feel free to try.
I think it is easier to grow carrots in pots of multipurpose compost. As long as the pots are 25cm deep or more it will work for most varieties. The big advantage is that you can keep the pot in the polytunnel to hasten germination and the carrots will grow long and smooth and be easy to harvest and clean. Just sow the seeds broadcast over the compost. Carrot seed is not the quickest to germinate and the seedlings grow quite slowly so you can easily sow a few radish in the same pot at the same time. These will be harvested well before the carrots need the space. This method, because the pots are raised, may also eliminate problems with carrot fly.
In the garden, carrots grow best in well dug, light, sandy soils. They are not great in clay soils and if the soil is full of stones it can caused misshapen roots. They must not be grown in heavily manured ground or the roots will fork or ‘fang’. Carrot seeds are light and can blow away before you cover them so it is a good plan to make a drill (shallow trench for sowing – about 1cm deep) and water this before sowing. Then the seeds will stick to the soil. It also makes sure the soil is wet so when you later water it will not just run off the surface. Always keep the area where the carrots are sown evenly moist after sowing. If the soil dries out as they germinate the seeds will die and nothing will appear.