Hardening off plants before you plant them

image from lovethegarden.com 

Hardening off plants before you plant them.  

​Clear, blue sky, a little wind out of SSE at 13MPH, and temperature getting warmer.  We started with 53F(11C) and should have a high today of 80F(26C). Soil temperature for our area today is 59F.  It has warmed up nicely.  ENJOY and stay safe.
 
Australia family and friends for their Wed April 22 will have a high of 68F(20C) with clear blue skies. An awesome fall day for them.  ENJOY and stay safe. 
 
This is what I will start to do this week and move out plants on wagons on the blacktop.  Two reasons to harden them off so they are ready to go into your garden and give us more room to plant more.  Broccoli, cabbage, collards, cauliflower, kohlrabi  along with the pansies will be the first to go out.  Another stage of gardening we do for you  “ we plant for you”  and we get the plants ready so they will grow in your garden.  If you grow your own plants orget your plants out of a greenhouse please hardened them off before you plant them.  More success with the plants in transplanting if you do this. 
 
Hardening Off Seedlings: How to Safely Transition Indoor Plants Outdoors
Written By:  Robin Sweetser
We sell hundreds of vegetable starts each spring and always remind our customers to harden off the plants before planting them in the garden. Surprisingly, many people have no idea what hardening off means.
What is Hardening Off?
“Hardening off” is the process of getting your indoor-grown seedlings safely accustomed to life outdoors. One of the most stressful transitions for a tender transplant is to go from life in a cozy greenhouse, where it has been sheltered from the elements, to life in the great outdoors.
Instead, give them a couple of hours daily in a protected spot out of direct sun and bring them in at night. Each day for a week or so, expose them to a little more sunlight and wind until they can stay out all day and are “hardened off.” See steps below.
How Long Does It Take to Harden Off Seedlings?
It takes about one week to 14 days. If you think this is lost time, think ahead. The plants still grow as they transition to the garden, but you won’t stall or stunt their growth (or kill them!).
You simply need to back up one week from your outdoor planting date (which differs by crop or plant). For many plants, you’ll start hardening off a week before the final frost date in your area. See the Almanac’s Planting Calendar, which is based on average frost dates.
Seedling Type          Hardening Off Time           Light Requirements           Notes
Tomatoes     7–10 days     Partial sun → full sun        Bring indoors at night
Peppers         7–14 days     Partial sun    Sensitive to wind
Lettuce          5–7 days       Dappled sun Quick acclimation
Cucumbers   7–10 days     Morning sun → full sun    Watch for wilting
5 Steps to Harden Off Your Plants
Think of your plants as if they were your children. Practice a little tough love now, and they will be ready to face the outside world soon.
Step 1: Choose the Right Seedlings
Choose seedlings that have grown at least a few sets of true leaves.
Step 2: Start Gradually Outdoors
Choose a mild, overcast day (no wind) when you remove the seedlings from their cozy greenhouse. Water the plants before they go outside.
Step 3: Protect from Sun and Wind
Choose a sheltered spot to place the seedlings. They’ll need protection from wind and dappled sunlight or partial shade. You can also cluster pots in crates, boxes, or buckets to keep the wind off. An unheated greenhouse could work, too. Just don’t place pots directly on the ground where they can easily be knocked over by birds or attacked by slugs.
The next day, leave them out for 2 more hours, with perhaps an hour’s direct sunshine in the morning.
Gradually increase the length of outdoor time over the next several days, gradually exposing them to more direct sunlight and wind. You can leave your seedlings out overnight if there’s no danger of frost.
Step 4: Monitor for Stress
Watch for wilting, leaf coloration, sunburn, dried-out leaves (wind), or any other signs of stress.
You can also shelter your baby seedlings in crates, boxes, or buckets to keep the wind off.
Please pay close attention to seedlings’ need for water since young plants in small pots dry out fast.
Step 5: Use Cold Frames or Floating Row Covers
If you aren’t home to tend your plants, the easiest way to harden them off is to put them in a cold frame that you can open during the day and close at night.
A cold frame that you can open during the day and close at night can serve as a nursery to harden off seedlings. ( NOTE  my mom used a cold frame I remember.  We had a steep ditch that was grass we mowed and she put the cold frame in that area with it opening to the east.)
Or, place them under a protective layer of reemay—the spun-bonded polypropylene sheeting used for floating row covers. This material is lightweight and lets in sunlight, water, and air. It captures some warmth, raising the temperature a few degrees above the outside air. You can make a tunnel by bending lengths of plastic pipe or heavy wire into hoops, pushing the ends into the ground, and covering them with reemay.
Floating row cover
Floating row covers can shelter your seedlings as they harden off (and also protect them from frosts).
Once crops have been planted into their final positions, be alert for unexpected cold snaps and cover tender crops if necessary. It’s a good idea to grow a few more plants than you need so you can hold some back, just in case. Bought plants may also need hardening off, especially if they have been kept in sheltered conditions.
Is Hardening Off Necessary?
Yes, it’s pretty important, especially if you live in a location with high UV index exposure. Think of this as a transitional space for coddled plants. After 5 to 7 days of this treatment, they should be able to survive a move to the big garden!
However, if you are already growing your plants under intense LED grow lights that boost the light levels, they may take less time to transition to direct sunlight. Some LED grow lights include artificial UV light yields, which growers have reported take even less time.
Further, you can increase the odds of seedling survival if you plant in the afternoon on an overcast day. Or set out in the shade or under a tree. Or, use a shade cloth or a layer of netting that offers 10% or 20% shade for a few days.
Frequently Asked Questions
Why is hardening off seedlings important?
It gradually acclimates indoor-grown seedlings to sunlight, wind, and outdoor conditions, preventing stress or plant death.
How long does hardening off take?
Typically 7–14 days depending on plant type and weather conditions.
Can I leave seedlings outside overnight?
Only if there’s no risk of frost. Start with short daytime exposure first.
 Can I speed up the process?
Gradual exposure is key. Using shade cloth, partial sun, or a cold frame helps protect plants while acclimating.
Here at the Almanac, we always advise patience. Never been in a rush to plant. Enjoy the process of nurturing growth and avoid shortcuts. That said, we’re always open to anyone who has tested new methods! Let us know about your experiences hardening off seedlings.
Taken from https://www.almanac.com/how-harden-seedlings
Till next time this is Becky Litterer, Becky’s Greenhouse, Dougherty Iowa [email protected]  641-794-3337  cell 641-903-9365  Beckysgreenhouse.com  Facebook Becky Kerndt Litterer or Becky’s Greenhouse