Neglecting to Transplant or Planting Out Too Early?

This season's crop of tomatoes is not looking quite as vigorous and healthy as last year's crop - why?

Here's what they looked like last year, in June of 2010, a little over one month after planting out:

and here's what they looked like this year in June, about 1 1/2 months after planting out (2011):

As you can see, they are much shorter and not as vigorous.

So let's look at the differences between last year and this year:

• Soil

No big difference; The soil is from the same batch, within the same bed, actually...just a few feet to the right of last year's crop.

• Amendments

Same as last year...but the clover cover crop wasn't as successful. This could have resulted in lower nitrogen levels, but the soil tests all said "high Nitrogen".

• Site

Just a few feet to the right of last year's crop. Little less shelter from the sun.

• Weather

Spring was perfect for the tomatoes this year. Very moderate temperatures with a good dose of rain. Pretty similar to last year. But temperatures have stayed lower than normal with a bit higher humidity. The tomatoes should be loving this.

• Seedling Care

• Transplanting

By transplanting, I mean 'potting up', not 'planting out' in the garden... This is where you start the seed in a small container, then as the seedling grows, you repot it into sequentially bigger containers before finally planting it out in the garden. I had never thought it was such a great benefit to the plant - until this year!

Last year I replanted my tomato starts twice before planting them in the ground. Actually, I replanted about 75% of my plants twice and 25% only once. I started my seeds in these handy-dandy floating trays:



Next, I transplanted them into these 2-inch (or so) cells:



and from there, most of the seedlings were transplanted into 1-gallon containers, shown here:



I would have transplanted all, were I not lazy (and out of good dirt). It would have been good to note the effect of transplanting again on last year's crop, but I didn't take note...

This year, though, none of my tomatoes were transplanted into 1-gallon containers from the 2-inch cells...although, I really don't think any of them were root-bound. So maybe this isn't the cause...

• Planting Out

In 2010, I waited until the second week of May to plant. This year, I planted them all in the last week of April, so this was almost 3 weeks earlier. Our last frost date is April 15, so it was 1-week after last frost, but we did get some very cold temperatures the first two weeks they were in the ground.One night got down to 33.5 degrees, and there were at least 5 nights where it was below 40 degrees.

The temperature guidelines for tomatoes vary from source to source, the minimum ranging from 45 to 54 degrees. One source goes further to say not to plant them until 2-4 weeks following last frost. !!! I think this is the culprit: I planted them too early. If I had waited another 2-4 weeks, they would have been root-bound, so they would have been root-bound by then.

The Verdict:

Next year: wait until 2-4 weeks after last frost to plant my tomatoes AND transplant them twice graduating to a 1-gallon container.