You can’t rush growth of celeriac
Gardeners occasionally tell me they have a problem in growing a certain vegetable.
Recently, it was the failure to grow a decent crop of celeriac, the turnip-rooted celery.
This plant needs a long growing season – 210 days from sowing to harvesting is not unusual. It also demands a fertile, but not recently manured, water-retentive soil.
A packet of circa 200 seeds of ‘Monarch’ (Suttons) costs 99p so there’s a tendency to sow thickly in a drill outdoors, but this plant needs space to develop, and that involves thinning out at the seedling stage, possibly later.
With April to May sowing, you are constantly playing catch-up in development. Far better start seed much earlier in pots.
A tiny pinch of seed atop moist compost is given a light covering of vermiculite and a spray of water, then stands in 12C to 15C until germination two to three weeks later. Remove all seedlings but the strongest and keep it well watered. Pot on as each develops and harden-off ready for planting mid-May.
Celeriac needs a constant supply of water and occasional feeding.