This weekend promises to be perfect for planting and if you want to do something more than putter, try planting a flat of something.
Flats--usually 64 plants--are the old-fashioned way of packaging flowers and ground covers. I didn't realize how old-fashioned they were until I noticed that a number of neighbors were fascinated by my planting primroses and ajuga from flats, as though they were watching one of those old hand-cranked apple peelers at work.
Planting from small pots or packs is far more common nowadays. The reason you don't see flats as much as you used to has to do with shrinking gardens and mixed plantings, but if you remember a particularly spectacular planting of flowers last spring or summer, it probably came in a flat because this is still the only way to buy flowers in quantity.
A Form of Discipline
I wouldn't normally plant from flats either, being a confirmed putterer, but they are a sort of discipline, forcing you to plant enough of one thing to really make a splash, and I decided that this coming spring, that's exactly what was needed in one shady corner of the garden.
In case there are others out there who have never planted anything from flats, let this old-timer tell you how satisfying a weekend project this can be.
Flats have been around forever--you can see them in old Flemish drawings, filled with cabbage seedlings. In California, they were once made of thin redwood boards, but are now made of plastic. They have always measured about 18 by 18 inches and usually contain 64 plants though some contain fewer because the plants are larger. They are called flats because they are only 2 1/2 inches tall.
The primroses I just planted filled an area about 4 feet by 8 feet (spaced 6 to 8 inches apart) with a few left over to tuck here and there. It was a particularly fine flat of English primroses and unusual in that they were not mixed but all one color--pink. I found it at Burkard Nurseries in Pasadena, one of a few nurseries that still carries lots of flowers in flats and orders from the growers its own special flats of certain flowers or certain colors of flowers, like mine. While I've never heard third-generation nurseryman Frank Burkard Jr. get very excited about anything grown in those little plastic six-packs, he was really impressed by these flats of primroses because they were so big and healthy, and because he could offer a flat of any color you liked, from orange to blue. For Frank and for me, flats are the real thing.
To plant flowers from flats, you must prepare the soil as you would for any new planting. It should be moist--not wet or dry--at planting time. Flowers from flats have short root systems and you need to pack the soil around their roots as you plant or they'll instantly dry out. You don't even need a trowel to dig the shallow hole. You can use your hands, a satisfying experience in itself.
To get the plants out of the flats, try one of two methods. Tip the flat on end and let the plants begin to fall out and then separate them by simply pulling them apart; this preserves most of the roots. If the roots are really knitted together, cut the plants out like pieces of cake, using an ordinary spatula or putty knife. Either way you will discover one of the reasons I like to plant from flats: the roots, cut or pulled apart, will not be rootbound and circling as they are in a pack or pot. Even though the plants may temporarily wilt (if they lost too many roots), they quickly regrow the necessary roots out into real soil. So once they get started, there is no slowing them down--unless you simply forget to water.
If the soil is moist, you only need to water the plants to settle them, one of the few times that standing there with a sprinkler, watering by hand, makes sense. Keep them constantly wet the first week, then gradually ease off on the watering as they become established. Fertilize with a liquid fertilizer from a watering can in about 4 to 6 weeks.
Come spring, they will be a spectacle, as only 64 plants of one kind can.
Ground covers, such as the ajuga I just planted, are always sold in flats, but that's a story for another weekend.