“Hardening Off” is the process of allowing plants to adjust from pampered conditions indoors to the harsher conditions outdoors. Seedlings especially need to adjust slowly to the harsh full sun, night temperatures, rains and winds.  If you do not allow your plants to adjust slowly, the shock from being placed outdoors all at once may cause them to die or under produce over time. What a waste of time after you nurtured those plants for so many weeks!

Prior to bringing your seedlings outside to harden them off you can introduce them to the windier conditions. Place an oscillating fan to gently blow over the seedlings. This will make them sturdier and more able to withstand the outside wind. Do not use heating mats under sprouted plants. Those mats were only used to start the germination process.  

“Hardening Off” may take a week to 10 days. Make sure the weather is mild before you start the process. If it is too windy, too cold or too hot do not put the plants outside.

Here are some easy tips to follow:

The first few days you will be bringing plants outside in the morning then back inside. Every day gradually add more time outside for the plants to adjust.

Here is the process:

Day 1—Place the plants in a sheltered, light-shade area out of the wind for 2-3 hours, then bring them inside.

Day 2—Place the plants in the same area as Day 1, but leave them out for 3-5 hours.

Day 3—Plants are in the same area for 4-6 hours.

Day 4—Today, water the plants well since they will be outside in the sun for 6-8 hours. Start them out in a sunny spot for 1-2 hours preferably in the morning so the harshest sun does not scorch them. Then move them to the shaded area for 6 hours.

From Day 5 on you will be placing the plants in the sun for longer periods. Day 5, water the plants before you put them outside. The first 1-2 hours will be in the sun and lessen the time in the shade. Every day add more time in the sun and less in the shade extending into the evening. Eventually the plants will be outside in the sun for the full day and part of the night. 

At this time, if the nighttime temperatures are 50-60°, leave them outside in a sheltered spot where wind will not harm them. Soon the plants will be outside all day and all night well able to withstand warm days, cooler nights and windier conditions.  Next you will be tackling transplanting the plants into the ground.  

(*see Transplanting in the May Newsletter)