"Hardening off" seedlings

I have now many seedings of perennals and vegetables which have sprouted and are anywhere from a few weeks to a week old. Some (pumpkins and zucchini) appear to look like they are going to take over quick, others (lettuce) seem to be dying for more sun.

Do I need to harden these off? How would I do that? I understand that the "growing season" is still about 2 weeks off. What will happen if I plant these sprouts now?

I don't have a cold frame, but could build one cheaply if I had to.

This is my first crop of veggies that will be going in earlier than June, and the first in a garden rather than a container.

Rob

AD - my understanding is that a temporary row cover only insulates to about 10° above the outside temps. There probably isn't that much more insulation gained with visquine
(6 mil???) stretched out & securely fastened over a hardware mesh "tunnel". Another option would be to place them in a clearish large storage box & replace the lid at night. If you have an area right next to your house where the heat collects during the day, they might do fine, too.
The process of hardening-off is to set them out during the day & bring them in when the temp starts to drop (early evening). Anything that is considered a hardy annual will be ok outside at night after about a week of the hardening-off process. Tenders - well, you run the risk of them shutting down their growth temporarily.
There is a variety of cloches sold online - I have tried several. the problem is with the tender plants - this is a dicey time of year with screwy temperature fluctuations. I am faced with the same situation, and have not yet decided how to proceed with the tender stuff. I don't want to take a risk with some of the rarer seed that has germinated.

If you can build a coldframe - that would be the way to go. You could rig it with a clamp-on light fixture inside (low-watt bulb) and this will keep the plants warm enough at night.
You would only need to keep that on overnight. Or - coldframe over a heat cable that is covered with sand. Then it becomes a "Hotbed" - supposed to work quite well. I have no personal experience with this, either.
Hope this helps.

AD, I use cold frames extensively and find them so useful. So if you can build one, I think you will find you get a tremendous amount of mileage out of the effort. However, everything I put in them has a good root system going, and I don't put things out until they have at least a second leaf (this is Half Hardy and Tender plants we are talking about - so that is most vegetables). Alternatively, I do find a few wire halfhoops pushed in the ground with gardening fleece over the hoops works well. Remember to take it off in the morning, leaving them exposed to weather during the day. Do be generous with the hoops making them no more than 18"/.5m apart or the fleece will sag during rain or (heavan forbid) snow. If you are doing this on a grassy area, watch for snails and slugs - they can wipe out an entire seasons growth in one night - as can blackbirds during the day! All of my coldframes have a 3"/.1m of sharp gravel in the bottom, and I nestle the pots into this - keeps them moist and stops them from toppling during watering, and slugs hate it). If you have any chicken wire making a wire tunnel that the fleece can go over will protect your seedlings from birds. If you don't want to spring for fleece, you can use bubble wrap/blister wrap, or even newspapers - it is a matter of keeping the frost off (amazingly even a well placed spiders web can make all the difference) - what you are doing is stopping the frost from settling on the foliage.

After 3-4 days, I start leaving the lids of the frame open a few inches at night, and then widen that to 12-15"/.3m. And that is the way they stay until ready for the wide world, and hopefully planting out.


Hope that helps.

Laurie - when you speak of gardening "fleece" are you referring to what we know as Reemay, or some such row cover? Or - do you have a handy link?

Here's another way if you don't have time to do a cold frame for this season:
put an inexpensive metal shelf up against your house where the sun will hit the wall. Make a heavy plastic cover for said shelving unit using a large clear plastic painter's tarp, or clear 'landscaping' plastic (shudder.). Fold the plastic so that it fits snuggly over the front, top, and sides of the shelving unit and use packing tape to hold the folds in place.
Put plants on shelves, cover them with plastic tarp at night, take off plastic in the morning. Leave plastic off a little longer the second night, etc. After about a week of this treatment, they will be hardened off.

alternatively, what I do is leave the greenhouse door open and the heat off. I start off by moving stuff out of the greenhouse during the day, back in at night, but then end up just leaving the door open all night and after a few days they are ready to go.

It's pathetic how many things I need to plant.

Pixy...LOL "It's pathetic how many things I need to plant."

Send some my way DH agreed to give me 10' more of that corner and 3' around the whole fence line....the fence line will be half shade...WOOHOO less grass again!!!!

It is nice to finally enjoy the greens of spring,
Carla

cocoa....
what is that little shrub to the left of the statue? pieris? and i know what you mean about seeing 'green' again. i go out everyday and check to see who has come up poking their heads through and check the progress on others. always ontop of my rhodies to see whos next!

Shokami2,

It is a very young Pieris, I put 2 in so I would have some evergreen in the garden. Don't worry when I get through with it (after it grows a bit) it will not look so formal...lol I like things a little more rustic than a rounded shrub.... Here is a picture of the one out front...

Well, night 1 passed. The lettuce sprouts are looking wilted, but everything else appears unshaken. The sprouts are in those manufactured trays with clear lid for window sill usage.

I let the plants spend the day of the deck which gets sun from about 10am to 5 pm, then I had them overnight in the trays with the top on under the eves of the house. I realize the sprouts probably got shocked by staying outside, but what the heck. The worst that could happen is compost, right?

I also have too much to build and plant. Right now I am doing a 15'x6'garden for veges in the back yard, on one of the slopes of the ditch. I am building what will be a 3' tall broken concrete wall for the down hill side. And the veges are going to have to wait on the garden being finished before they can get planted. But 15 feet of wall is making me think about 100 feet, as I like the way it looks, and it would allow me to plant along the fence so much better.

Yeah, yeah, I owe pictures. Soon.

Rob

What I have done is make hats outta of milk jugs, cut the bottoms off, and walla you have mini greenhouse, I remove them during the day and put them on at night. ( I have someone do it for me, I am never home)

^_^

This message was edited Apr 3, 2008 8:46 PM

Nice idea, Mary!!

Today while the seedlings were out in the afternoon, I found that the lettuce and the cherry tomato seeds seem to have taken it pretty hard. I am pretty sure that the lettuce is quite DOA, and the tomatoes are on the edge.

I brought everybody inside tonight to see if that would help the tomatoes. Zucchini, pumpkins, heirloom tomatoes, and the peas seem to have been untouched by being outside last night, and are just seeming to be asking for more of this outside stuff. But I am not going to be able to attend to them until the weekend.

This has been the strangest weather, just when you think its safe, the sky falls in. LOL
Hope the babies will make it.
Tils
^_^

Analog, just don't do too much moving of them from warm to cold, back to warm, etc. They won't like it. Better to put them in a sheltered position outside and keep them covered with a plastic top or cloche (use a clear 2 liter pop bottle with the bottom cut off). Plastic or cloche on at night, off in the day, for a couple of days, then leave them. All of my seedlings are outside for good now, and uncovered.

Wish I knew that earlier. I now seem to have lost most of my tomatoes. And I was wondering why. So I will keep them out 24/7 now. Luckily Gordon brought by a flat I can use for drainage last night.

Rob

I think that is called trial and error, live and learn, done my share and still learning LOL

Rob, why are you trying to grow warm weather crops like Tomatoes, Zucchini sooo! early? I just started my Tomatoe seeds indoors under lights. then I will pot them up in a few weeks and move them into my unheated greenhouse until late May. by then I will have repotted then a couple of times and they'll be 2ft tall. if you try to grow them ( warm weather crops ) too early they just rot or shiver. until it gets warm. also they get cool shock and go into dormancy, which takes them several weeks before they start growing again. better luck, Jim

It was just a beginners error. I will try them in a little bit, as I have no greenhouse to grow them in. If someone can put up a list of temperatures before planting whatever outside, I would love to see it.

Clueless Rob
who just composted a few sprouts.

Hey Rob, My first ever little GH was made from a cardboard box, believe it or not. I took a large box and cut 1" out from all corners, including the lid. and made a skeleton kinda box, then wrap plastic over the top, it work great. Its a temp kinda thing, but it works.
^_^
Tills

Hummm. So should I do that then start the maters? Humm.

Rob
who loves low tech stuff.

You can also make a dome with a base and two crossing supports out of pvc pipe and then cover them with plastic, anchoring the plastic as you wrap it (unless you want to cut) with clamps. I used to have one like that - should probably try it again.

Rob, no worries. Definitely trial and error, live and learn stuff. Personally, I generally put things outside way too early in the year and then have to move them back in for a week or two. It's because hope springs eternal and I always am ready for spring about a month before it actually comes. However, I have found through many seasons of trial and error that Jim is completely correct when he says to wait until late May. Putting them out earlier really doesn't make them grow bigger or faster. i think it's just one of those things you learn as you go.

Yep, wisdom comes from making mistakes. And if we only kill plants, we are doing pretty well.

Rob, starting the Tomatoes indoors, they need light if inside or they will be spindley. and then making a small greenhouse like katie suggested will work the same as a large greenhouse. just something to collect heat. with some ventlation on warm days. of course there won't be too many of those days until June around here. we all learn by doing, what's the propagators motto? " been there killed that " Jim

LOL - a lot of heads were nodding on that one HJim!

I, too start some seeds earlier than I should, and go through the hardening off dance. If you provide a place of comfort for your seedlings (as has been described) it makes this process a lot easier.
I use the last (approximate) frost date as a guide for hardy annuals, & memorial day for the tenders. But I'll be the first to admit - it requires much patience!

Actually, I believe living in the Pacific northwest in early spring requires much patience. Today, I was weeding with an umbrella in my hand. Curse the weather, pull a weed, then curse the weather, pull another weed, you get the idea.

"Been there, killed that." ROFLOL!! So very true!!

LOL done more than my fare share, poor things.



This message was edited Apr 6, 2008 10:44 PM

This morning I said last rights over my tomato starts.

"Looks like compost, guess they don't need to be moved. If they dry I can just pick them off, and use the pots again."

It was very solumn you understand. Not that I haven't killed $1000 worth of plants 'hardening them off' back a few years ago. Sigh.

Everything else appears to be doing pretty well. The Lavender, Kniphofia, Oregon Peas, Bush Beans, and pumpkins seem to be relishing the weather.

Ah. Well I am glad you gave them a proper burial. Apparently we have not made proper offerings to the weather gods and they have visited cold, rain, and sleet upon us. Woe unto us!

AD - may I suggest that you not reuse the pot/soil, just incase it wasn't the cold that got them. Toss the lot on the compose heap and let the piles heat take care of it. Then spring for some fresh compost and sow again.