Five weeks into autumn, and with the weather staying mild and pleasant, its time to harvest the potatoes and plant the carrots while the soil remains warm and un-water-logged by too frequent rain. I’ll be planting four varieties from commercial seed packets this season, as I need to re-establish some diversity in my carrot seed collection, which has concentrated on ‘Nantes’ but does not yet include ‘Topweight’, ‘Chantenay’ and ‘Purple’. (Just how I keep these four from cross-pollinating when the carrot blooms form in two year’s time is a story for another day!)
Purple carrots? According to the Seed Savers’ Handbook the origin of carrots is: ‘Native to many regions, including parts of Europe, northern Africa, Afghanistan and Central Asia. Carrots were first used as medicine. They come in many colours. Purple carrots arrived in Western Europe from the Middle East in the Middle Ages. After considerable selection, these evolved into yellow ones. Not until much later did a Dutch gardener obtain a mutation which had the orange pigment familiar today. By the Middle Ages the Japanese had developed unusually long carrots adapted to their cuisine.’
Carrots need a deep friable loamy soil free of coarse material and without too much nitrogen fertiliser, as this causes ‘forking’ of the carrot root. The best way to create such a soil is to plant potatoes as the lead-in crop; both the mounding of potatoes and the deep digging needed to harvest the potato tubers creates a rich and friable loam. I’ve known for some time now that this small crop of ‘Dutch Cream’ potatoes was going to be disappointing, and I haven’t been disappointed – they're rubbish! (Digging around the potato plant roots when the plants were still green and thriving showed no sign of the usual large tubers present; this sometimes happens with the wrong variety in the wrong place). However, the soil in this small spot – perfect for planting high density carrots – is now just about ideal – deep and crumbly with plenty of organic matter to feed the roots and later, us.
Once the deep digging has been completed with the ‘potato hoe’ – a far better implement than a garden fork – the soil surface is raked level and the last of the mulch and bits and pieces removed. Carrot seeds are fairly small and slow growing, so they need to be kept moist despite being planted in the shallow surface layer just a few millimetres down. I simply scatter the carrot seed across the surface, then use a large 5 mm sieve to cover these gently with more fine crumbly soil particles before tamping down by smacking the soil surface gently with my open hand to ‘bed in’ the seed.
The trick to raising carrot seeds is to find a way to water this very narrow surface layer while preventing it from drying out during sunny weather. In the old days, we used to do this by covering the seeded area with second-hand underfelt, often to be found on footpaths during hard rubbish collection week. Sadly, this wonderful material is becoming scarce – modern carpets use a foam rubber underlay to give it that comforting springy feel. So these days I use folded shade cloth lain on the surface; one can water through this with the watering can while it keeps the soil surface shaded for the first four or five days needed for carrot seed germination. The corners of this shade cloth are pinned down by bricks, or by wooden stakes laid across them. I check every few days to see if the carrot seeds are up; at this point they are rather yellow and in need of sunlight to keep going, so the cover is permanently removed. When the carrots are some weeks old and standing approximately 50 mm (2”) high, thinning can begin to a spacing of just slightly more than the diameter of a fully grown carrot. This ‘scattered seed’ method gives me more carrots per square metre than the old business of trying to raise carrots in rows. As for the old mulch that covered the potato crop during the heat of summer, its barrowed down to the chook yard and dumped for the chickens to scratch through it, turning all those slater beetles and earwigs into tomorrow's eggs.