Different dormant plant sizes. Photo: K. Demchak, Penn State
Here are a few of the things that are most important when it comes to establishing a healthy planting:
Working the soil when it's not quite dry enough is probably one of the worst things you can do for your strawberry plants. In a friable soil with good structure, the plants' roots will make good soil contact, which allows plants to take up the moisture and nutrients that they need to grow.
Plants planted in cloddy soils just won't grow well, in part because of poor root contact, but also because it is difficult to set the plants at the correct height. Either the plants settle too much, and soil washes into the crown making it rot, or the plants end up perched too high, and the roots become exposed and dry out. Neither scenario ends well. And of course, improving the soil organic matter content is something that helps with soil structure and drainage, so that is something to factor into crop rotations for the long haul.
This means making sure beds are trickle-irrigated in plasticulture plantings before planting, and then giving them a day or two to drain before planting. Planting is a lot easier when the beds are nicely moist, not dry or sopping wet. Keeping the plantings well-watered in dry spells will allow the plants in matted-row plantings to produce enough runners to fill in the beds, and will make it easier for the runners to root. It will also keep those plasticulture plants humming along.
One critical point with dormant plants is to leave the plants at the nursery until you are ready to plant, unless you have storage facilities that don't have apples in them and where the plants can be kept very cold (30-31 degrees). If the plants are held at warmer temperatures for even a couple of extra weeks, they are using carbohydrate reserves just to stay alive that they should have been putting into growing leaves and roots, plus they tend to send out leggy leaves that get broken off at planting.
A second point is to order a few more plants than you need, and give yourself the option of discarding very small ones. It seems that some smallish plants often are in the orders, but very small weak plants seen to spend a good part of the summer growing to the size they should have been in the first place, when instead they should be producing runners to fill in the row in matted-row plantings, and branch crowns to increase yields in plasticulture ones. In matted-row plantings, those early-rooting daughter plants will provide much of the yield for the following year.
In plasticulture, a higher proportion of the small plants don't survive if planted, and those that do produce lower yields, resulting in a decrease in overall yields. It takes just as much (or more) time and money to take care of a partially filled weak bed as it does to take care of a vigorous one, and the payback is worse. In this photo, the two plants on the left would be fine to use, while the one on the right, only measuring about ¼" in diameter, is too small.
Nitrogen (in moderation)
Notice that your plants aren't looking so green, or aren't growing all that well? First, makes sure there is sufficient moisture in the soil, and if lack of moisture isn't the problem, 20-25 or so pounds of nitrogen per acre in matted row plantings, along with enough water to give the plants a good drink, often makes them jump. Apply the recommended fertilizer rates (according to your soil test results, of course!) at planting, and then fertilize when the first runners start being produced, and again in mid-August. In plasticulture plantings of June-bearers, the rule of thumb is still 60 pounds per acre of nitrogen pre-plant incorporated before planting, and 30 pounds of nitrogen per acre in the spring. For day-neutrals, 60 pounds per acre pre-plant and 1 pound of nitrogen per acre per week during the growing season has worked well.
The bottom line is that if the planting starts out vigorous, you won't have to spend money and time trying to coax it along later. Chances are that the plant growth will outpace much of the damage from diseases and insects, and competition from weeds. All of this together makes planting care easier in the long run, and helps ensure a good return on your investment.