You can start growing Autumn leeks indoors by mid February but make sure they’re an early variety like ‘Hannibal’ or ‘Blue Green Winter’. They will take about 8 weeks from sowing to planting out so make sure you have the space to keep the trays inside until it’s warm enough to plant out in April.
Now, enjoy watching Klaus teaching and me learning how to grow leeks one of our new Quickcrop ‘Grow your own’ video series.
Leeks are best sown in modular trays as described in the previous section. Make a hole with your finger in each module about 1.5 cm deep and sow 2 seeds per cell. You will a temperature of between 8° and 30° so unless you have a heat mat or propagator they will need to be germinated on a south facing windowsill. I have mine on a mat at about 15° and they’re all coming up fine.
When the seedlings appear above the compost you can remove them from the heat source. Remember that the seeds only need the heat to germinate, after that they need light. Because light levels are low in early Spring leaving them on the heat mat will result in tall, leggy seedlings.
Keep the compost in the plugs moist being careful not to over water, we recommend watering in the morning rather than the evening as the colder night time temperatures coupled with cold water can set the young plants back. In February your watering will be minimal anyway with low temperatures and little sunlight.
You will be planting out the two plants together when the roots are able to hold the compost plug together, this will be about 8 weeks.
As we are planting our leeks in two’s we need to increase the usual spacing from 15cm to 30cm apart. Leeks are planted quite deeply so you can make a hole about twice the depth of the plug when planting out, just make sure the forked part of the stem is above ground. Firm around the seedling to get good contact with the soil.
I would mention at this point that I’ve come across an excellent Irish made product for planting leeks and other vegetables keeping them weed free. Like all good ideas it’s very simple and involves a weed protector mat with the required spacing holes cut in. The product is GrowGrid, you can read more about it in a more detailed article here but suffice to say it’s very good. Leeks and onions have a shallow root system that can easily be damaged by weeding so it makes sense to avoid disturbance around the plant as much as possible. TIP: If you’re using a GrowGrid or a plastic sheet solution make sure you feed your soil first as you won’t be able to once the mat is down. We recommend 1 bucket of envirogrind per square metre.
Now here’s some insider information, to be fair Klaus told me this but I’m a good little pupil and usually do what he advises because it always works:
- Many gardening books advise you to plant leek seedlings bare root in a hole made by a dibber. If you have a sticky clay soil like me this will be a disaster as the dibber compacts the edge of the hole making it difficult for the roots to work themselves into the soil. Just use a trowel unless you have nice crumbly soil.
- There is a practice when planting leek seedlings to snip the roots and tops with a scissors but this has now been shown to effect the yield. I’m not surprised, good roots are so important, why cut them? Anyway, don’t bother, just pop the happy little plug with 2 seedlings into the whole and firm in nicely.
That’s it. Remember leeks are quite a hungry plant so prepare the bed with plenty of compost or rotted manure. They will also benefit from a top dressing of seaweed – poultry manure pellets once or twice in the season.