Why can't I grow leeks?!

Molly Bloom

I've been growing my own fruit & veg for 30+ years and have never grown a decent crop of leeks. It must be me, they're not that hard to grow, surely? The leaves buckle up as they're growing (every time!) and I get an infestation of those little brown grub things (every time!). I start them off in small trays, pot them on into individual root-trainers when they're 3" high, then plant them out when they're as thick as my little finger (which, I admit, IS quite skinny). I must be doing something wrong, but what?

BobTheGardener

The problem is allium leaf miners which are active during two main periods of the season.  The only thing you can do is grow them under a fine mesh cover such as enviromesh.  The flies which lay the eggs are very small (3mm) so the holes in the netting have to be smaller than that.  These links may help:

https://www.rhs.org.uk/advice/profile?pid=643

https://www.theguardian.com/lifeandstyle/2018/mar/24/how-to-beat-allium-leaf-miner-leeks

purplerallim

It seems this years leeks haven't done well for quite a few growers. I planted some for the first time in autumn, and even though they look ok, they are not very big so not sure if I should use them now or give them more time.🤔 My nemesis seems to be onions, I can only grow red spring onions.🙄

Palustris

You could try dropping a slow release fertiliser tablet down the hole in which you plant the baby leek. I used to get good results like that until the leaf miner and Leek moth finally beat me.

Nollie

Mine were pretty small this year too, after the very hot, dry summer, but usually they do well for me and grow big and fat. Have you tried sowing them direct in a finely raked seed bed Molly? They are very hardy and grow well outside so maybe don’t need all that cosseting and transplanting. They do need regular watering and a reasonable but not too rich soil to grow in.

I sow mine as thinly as possible in shallow drills in the seed bed, thin them out in situ as necessary then lift them when barely pencil thick. I trim the roots to a couple of cm, drop them into deep dibbed holes in the main allium bed (in the spot vacated after the garlic harvest) so that at least half their length is below soil level. Water the holes until the water spills out but don’t firm them in. They flop at first but within a week or so right themselves and grow to fill the hole.

I net all veg seedlings to protect from my pesky digging/crapping cats, rather than leaf miners (which, fingers crossed, I haven’t suffered from so far) then remove the netting when they are big enough to fill out the space and the cats leave them alone.

Molly Bloom

Thanks everyone! So this year I'll try sowing them direct, giving them a shot of feed at the roots and using enviromesh. What a lovely bunch of folks you are!

Allotment Boy

I have had mixed results too over the last few years. There is a pheromone trap for leek moth but I don't know about the  leaf miner, but our other issue on my Allotment site is white rot which affects all of the Allium family.

Nollie

I would also try laying off the fertiliser, Molly. The one year I inadvertently fertilised my alliums by topping up the bed with fresh compost they grew all soft and distorted. I know others do fertilise alliums, and it does depend on your soil, but they definitely do better for me without. If grown too ‘soft’, perhaps that also encourages pests.

Molly Bloom

It's odd how some things thrive for some people but don't for others (there's a PhD thesis in that for someone!). I always get great results with onion sets but never with seed, they just tend to melt into the earth. I start my onions in small pots in the greenhouse, then plant them out a couple of weeks later when they've got a small sprouting of green at the top. Don't tend to feed them but I water every day unless it rains. Garlic is usually so-so - adequate but nothing to make your jaw drop. Ho hum.

Nollie

True, I can’t grow celeriac or brassicas like broccoli and cabbage. Too hot here in summer, they get so far then give up!