Hardening Off

After it was suggested that my plants have "fungus mites", I was told to start bringing my seedlings out into the light and air.  So, I decided to start hardening them off.

 

 

I know the goal of hardening off is to get the young plants gradually used to hotter and colder temperatures.  The other night, I left the plants out until it reached 50F.  The tomato plants looked like they were cringing:

They did recover, and I've been putting them outside and keeping them there until the temperature hit 48F.  When I brought the seedlings in, the eggplant seedlings, cantaloupe seedlings and cucumber seedlings didn't look so hot.  They looked very pale, and like they were losing their green color.

I went on line to see if I could find out more about hardening off.  I learned that certain plants should not be kept outside in temperatures below 60F, because they are tender.  I also read that the hardening off process should begin a week or 2 before planting day.

I have decided to bring the plants in when it gets down to 60F, and take a couple of weeks to fertilize the plants a bit.  I am starting with Super Thrive.

Recommendations Taken From Washington State University

1. Harden off gradually, so that seedlings become accustomed to strong sunlight, cool nights and less-frequent watering over a 7-10 day period.
2. On a mild day, start with 2-3 hours of sun in a sheltered location.
3. Protect seedlings from strong sun, wind, hard rain and cool temperatures.
4. Use an automatically opening cold frame, if you have one.
5. Increase exposure to sunlight a few additional hours at a time and gradually reduce frequency of watering, but do not allow seedlings to wilt. Avoid fertilizing.
6. Keep an eye on the weather and listen to the low temperature prediction. If temperatures below the crop's minimum are forecast, bring the plants indoors or close the cold frame and cover it with a blanket or other insulation.
7. Know the relative hardiness of various crops. Onions and brassicas are hardy and can take temperatures in the 40's. After they are well hardened off, light frosts won't hurt them. Warm-season crops such as eggplants, melons and cukes prefer warm nights, at least 60° F. They can't stand below-freezing temperatures, even after hardening off. (See chart below for more detail.)
8. Gradually increase exposure to cold.
9. Root-prune plants in flats a week before setting out. Use a sharp knife and cut down to the bottom of the flat between the plants. Water thoroughly.
10. After transplanting to the garden, use a weak fertilizer solution to get transplants growing again and to help avoid transplant shock.

Recommended Minimum Temperatures

Hardy	40° F.	Broccoli, Brussels sprouts, kohlrabi, cabbage, onions, leeks, parsley
Half-Hardy	45° F.	Celery, Chinese cabbage, lettuce, endive
Tender	50° F.	Squash, pumpkin, sweet corn
	60° F.	Cucumber, muskmelon
	65° F.	Basil, tomatoes, peppers

 

This chart has been taken from Washington State University

 

 





Potting Soil

This is the first year that I have ever had any success with growing plants from seed, but what a learning experience it has been!

One of the challenges I always face is "damping off" , or "root rot", due to over-watering.  This year (aside from my first try at pepper plants) everything has gone really well, thanks to peat pellets. I tried 2 different kinds, peat and soil pellets and like the peat pellets better (I lost a whole flat of marigolds using the Jiffy pellets).

I noticed that the seedlings I transplanted first have done so much better than the seedlings I did in the following weeks.  I think it's because of the potting soil.  The first potting soil I used had a slow-release fertilizer incorporated in it.  Then, when I ran out, I was tempted to buy a really cheap potting soil called Jolly Gardener.  Well, this gardener isn't feeling too jolly!

The second potting soil was damp in the bag, and felt really heavy.  I think the dampness hurt the roots, because the plants have pretty much stopped growing.  I have tried a new potting soil called Fox Farm Ocean Forest (FFOF) which has been touted all over gardening forums.  Still, my seedlings seem dejected.  I think the longer the seedlings sit around in their peat pots, the more they lose energy to grow.

One of the biggest questions I have had is how and when to fertilize the plants.  Again, the first potting soil with the slow-release fertilizer seems to have worked best.

Last week, I started getting extremely concerned because I noticed some of the tomato leaves looking a bit shriveled, and I discovered some tiny bugs floating around.  Someone at the garden center told me that I probably have fungus mites, due to dampness.  Darn that Jolly Gardener! Her recommendation was to bring the plants up out of the basement to get some air and dry off.  So that's what I did.

Any way, here is a photo comparing two tomato seedlings, both sown on April 6th.  What a difference!

In all fairness, the plant on the left was sitting in a peat pellet for at least 2 weeks while I waited for it to develop true leaves.  I'm not sure why some of the plants grew so much quicker than the others.