Alternatives to hardening off crops

[Laura Hillier]

Hi everyone,

Here at the GYO office we were discussing hardening off seedlings. Do you give your crops time to get used to chilly outdoor temperatures before they're planted out? We were just wondering if you have tried any nifty alternatives to this process and what outcomes you've had? Did your plants thrive? Let us know!

Your answers may be edited and published in the April issue of GYO.

Laura
Editorial Assistant
Grow Your Own

[alldigging]

I've done several methods.

The leaving them outside the greenhouse during the day and then accidentally forgetting about them one day and leaving them out overnight. Worked out ok but I was lucky I think.

I use a cold frame that's open all of the time and that gives plenty of shelter to plants. From there they can be taken out and put on the allotment.

There's the reckless 'oh just put them outside' technique when the greenhouse is full. And that was fine too.

I do think it depends so much on the weather though - a bad late frost and I'd have had plants that might have been as successful.
2012 was a bad year for slugs deciding to eat things I was trying to harden off.

[rustylady]

There are no alternatives to hardening off, just different ways of doing it.

[VirginVegGrower]

I always harden off. From windowsills indoors, they go to the greenhouse benches in covered trays. From there during daytime hours to outside coldframes. Then it's day and night time in coldframes to final planting outside. I move in ever "increasing" circles with seed trays and pots.

[veggiechicken]

The alternative to hardening off is sowing direct - and praying!

[kathycam]

I'm hoping my polytunnel will help keep my windowsills and balcony a little clearer, as last year there wasn't much space to move. Hopefully slightly later sowings in the polytunnel might help. But any plants sewn indoors do need to be hardened off, to make sure they get used to being outside gradually.

[Aberdeenplotter]

If the weather is kind, plants coming out of a warm, humid, wind free envirnonment will grow away just fine. On the other hand, as is more likely in our climate, the outside growing environment is likely to be less favourible and this may cause a check in growth and they may well sit and sulk for a spell indeed the check in growth may be irreversible. Until the risk of nightime frosts are gone, it therefore makes sense to gradually acclimatise plants to outside temperatures(that is what hardening off means) over a period so that when they are planted out there is no shock to the system and the plants should then grow away without problems.

[SarzWix]

It isn't only the temperature which has to be considered when hardening off; because plants grown indoors/under-cover have 'soft' foliage they can't stand wind either as it dries the plants outas much as sunshine does. So if you want to skip the traditional hardening off of taking plants in and out for a couple of weeks, you need to find some other way of gradually exposing them to the elements. That could be a cold-frame which is opened increasing amounts as the days go by, or a simple cloche covered first with polythene and then with fleece and then netting. I've never had any success with just planting out and hoping for the best though; the weather up here is just too harsh...

[carolineholding]

I have a sheltered spot, our L shaped Home faces southwest so I either sew and over winter stuff in the 'L' sweet peas and broad beans have both been sitting there in toilet roll tubes all winter or I bring things out there to harden them off.

[Alison]

If you sow and grow on in the warm and then don't harden off then you will get plants that are shocked by the sudden changes which can only be a bad thing. They may recover fine but, unless you are very lucky with the weather then you will get a pause in development which isn't worth the risk. The only way to avoid having to harden off in the UK climate is to sow direct at which point you start getting a greater slug risk.............

[chriscross1966]

A lot of stuff starts in propagators indoors, moves to the warm bench in the GH, then open staging in the GH, then either the rather open polytunnel on the plot or the patio, possibly via the carport, and then out...

[lottie dolly]

This year i have made some outdoor beds with plank sides and a sheet of hard poly double glazed on top,held down with bricks,the inside has 3 devisions for rotation,and potting compost,the seeds are sown straight into the ground,then as they grow and need to be hardened of,the lid can be left of /ventilated,eventually cover with netting,before digging up for their final position,this i will use mainly for brasicas and leeks.

[snakeshack]

I put out watercooler bottles with the bottoms cut off to warm the soil where tomatoes and squashes are to go about a week before planting out,then after planting out under these for about a week I gradually prop the bottles up a bit at a time over 2 weeks before removing.

[rabbit]

I was just reading in a Joy Larkcom book that there is an alternative method to hardening up, and it is a traditional japanese method that apparently some commercial growers use too. Apparently physically brushing the seedlings to mimic the effect of wind has the same effect!

[Linzy]

My greenhouse is unheated and missing a panel of glass so its abit chilly in there. But my seeds always come up and grow nicely. And its got the added advantage of not having to harden stuff of as other than the wind they are used to the cold.