Directions have already been given for preparing the best soil for house plants. This soil, sifted through a coarse screen—say a one-half inch mesh—is just right for "pricking off" or transplanting the little seedlings.

Use flats similar to those prepared for the seeds, but an inch deeper. In the bottom put an inch of the rough material screened from sods and manure. Give this a thorough watering; cover with an inch of the sifted soil, and wet this down also. Then fill the box nearly level full of the sifted soil, which should be neither dry nor moist enough to be sticky. Take care also that this soil is not much—if any—colder than the temperature in which the seedlings have been kept.

It is usually best to transplant the seedlings just as soon as they are large enough to be handled, which is as soon as the second true leaf appears. Nothing is gained by leaving them in the seed boxes longer, as they soon begin to crowd and get lanky and are more likely to be attacked by the damping off fungus than they are after being transferred.

Find a table or bench of the right height upon which to work comfortably. With a flat stick, or with a transplanting fork (which can be had for fifteen cents) lift a bunch of the little plants out, dirt and all, clear to the bottom of the box. Hold this clump in one hand and with the other gently tear away the seedlings, one at a time, discarding all crooked or weak ones. Never attempt to pull the seedlings from the soil in the flat, as the little rootlets are very easily broken off. They should come away almost intact, as shown facing page 48. Water the seed flats the day previous to transplanting, so that the soil will be in just the right condition, neither wet enough to make the roots sticky, nor so dry as to crumble away.

Take the little seedling by the stem between the thumb and forefinger, and with a small round pointed stick or dibber, or with the forefinger of the other hand, make a hole deep enough to receive the roots and about half the length—more if the seedlings are lanky—of the stem. As the little plant is dropped into place, the tips of both thumbs and forefingers, by one quick, firm movement, compress the earth firmly both down on the roots and against the stem so that the plant sticks upright and may not readily be pulled out. Of course there is a knack about it which cannot be put into words—I could have pricked off a hundred seedlings in the time I am spending in trying to describe the operation—but a little practice will make one reasonably efficient at it.

When the flat is completed, jar it slightly to level the surface and give a watering, being careful, however, to bend down the plants as little as possible. Set the plants on a level surface, and if the sun is bright, shade with newspapers during the middle of the day for two or three days.

From now on until ready for potting, keep at the required temperature, as near as possible, and water thoroughly on bright mornings when necessary, but only when the drying of the surface shows that the soil needs it. Above all, give all the air possible, while maintaining the necessary heat. The quality of the mature plants will depend more upon this precaution than upon anything else in the way of care.

The little seedlings are sometimes put from the seed flat directly into small pots. I strongly advise the method described above. The flats save room and care, and the plants do much better for a few weeks than they will in pots. Where room is scarce, it is well to transplant cuttings into flats instead of potting them off. As soon, however, as either the transplanted plants or cuttings begin to crowd in the flats, they must be put into pots. How soon this will be depends largely, of course, upon the amount of room they have been given. As many as a hundred are often set in a flat 13x19 inches, but it is well to give them twice as much space as that if room permits.

POTTING

Cuttings and small plants are put into two-inch or "thumb" pots. Some of the larger growing geraniums or very sturdy plants require two-and-one-half inch pots, but the smaller size should be used when possible.

The soil for pots up to three inches should be screened, but not made too fine. A coal-ash sifter, or half-inch screen will do. The soil should be made up as directed in Chapter III.

The pots should be thoroughly cleaned with sand and water, or by a several days' soaking, and then wiping out with a cloth, if they have been used before. An old pot, with dirt sticking to the inside and the pores all clogged up, will not do good work. Old or new, they should be immersed in water until through bubbling just before using; otherwise they will absorb too much moisture from the soil.

The method of potting should depend somewhat upon the condition of the roots of the cutting. If they are less than half an inch long, as they should be, fill the pot level full of soil, make a hole with the forefinger of one hand; insert the cutting to about half its depth with the other, rap the bottom of the pot smartly against the bench to settle the earth, and then press it down firmly with the thumbs, leveling it as the pot is placed to one side in an empty flat. (The jarring down of the soil should precede the firming with the thumbs, as this will compact the soil more evenly within the pot.) This should leave the soil a little below the rim of the pot, making a space to hold water when watering; and the cutting should be so firmly embedded that it cannot be moved without breaking the soil.

With cuttings whose roots have been allowed to grow an inch or more in length, and plants with a considerable ball of roots—as they should have when coming from the transplanting flats—it is better partly to fill the pot. Hold the plant or cutting in position with the left hand and press the soil in about it with the right hand—firming it as directed in the former case. With a little practice either operation can be performed very rapidly. Florists do four to five hundred pots an hour.

When for any reason it is necessary to put a small or weakly rooted plant or cutting, or a cutting that is just on the point of sending forth roots, in a pot that seems too large, put it near the edge of the pot, instead of in the middle. This will often save a plant which would otherwise be lost, and at the next shift it can, of course, be put in the center of the pot.

If no small pots are at hand, several small plants or cuttings can be put around the edge of a four-or five-inch pot, with good results. Care must be taken, however, not to give too much water.

As soon as the little plants or cuttings are potted up, give them a thorough watering and place them where the holes in the bottoms of the pots will not be clogged with soil. A large flat, in the bottom of which an inch of pebbles, coarse sand or sifted cinders has been put, will be a good place for them. Keep shaded during the hot part of the day for three or four days. At first the pots may be placed as close together as possible, but in a very short time—two weeks at the most, if the growing conditions are right—they will need to be put farther apart. Nothing will injure them so quickly as being left crowded together where they cannot get enough air. Better, if necessary, give or throw away half of them than to attempt to grow fifty plants where you have room for only two dozen.

As before, water only when necessary, i.e., when the surface of the soil begins to look whitish and dry. Then water thoroughly. Until by practice you know just what they need, knock a few out of the pots, say fifteen minutes after watering, and see if the ball of earth has been wet through to the bottom; if not, you are not doing the job thoroughly. If the pots do not dry out between waterings, but stay muddy and heavy, either your soil is not right or you have used pots too large for your plants.

REPOTTING

In the course of a week or two, if a plant is knocked out, the small white roots may be seen coming through the ball of earth and beginning to curl around the outside of it. The time for repotting the young plants will have been reached when these roots have made a thick network around the ball of earth, but before they become brown and woody; that is, while they are still white and succulent—"working roots," as the florists term them.

[Illustration: Potted cuttings ready for shifting to a larger pot. From left to right, ivy geranium, snapdragon, geranium and dusty miller]

[Illustration: Some plants, like Rex begonia, will strike root from their leaves if perforated with a knife into damp sand]

[Illustration: In all potted plants an important detail is the placing of rough drainage material, such as broken pieces of pot, charcoal, ashes, etc., at the bottom, to prevent moisture from settling in the soil and souring it]

The shift, as a general rule, should be to a pot only one size larger, that is, from a three to a four, or a four to a five.

Remove the plant from the old pot by holding the stem of the plant between the index and middle finger of the left hand, and with the right inverting the pot and rapping the edge of the rim sharply against the edge of the bench or table.

Before putting the plant into the new pot, remove the top half inch of soil and gently loosen up the lower half of the ball of roots, if it is firmly matted.

Put soil in the bottom of the pot to such a depth that when the ball of roots is covered with half an inch or so of new soil, the surface thereof will still be about half an inch below the rim of the pot. Hold the plant in place with the left hand, and with the right fill in around it, making the soil firm as before. Water and care is the same as after the first potting.

Pots four inches or over in size should be crocked to make certain of sufficient drainage. The best material to use is broken charcoal, in pieces one-half to an inch in diameter. Pieces of broken pots, cinders or rough pebbles will do. Be sure that the drainage hole is not covered; if pieces of pots are used, put the concave side down over the hole, as illustrated facing page 41. The depth of the drainage material, or crocking, will be from half an inch to three inches, according to the size of the pot. Over this rough material put a little screenings, leaf mould or sphagnum moss, to prevent the soil's washing down into it. Then fill in with soil and pot in the regular way.

The time for repotting house plants is at the beginning of their growing season. It varies, of course, with the different kinds. The great majority, however, start into new growth in the spring and should be repotted from the middle of March to the middle of May. Plants kept through the winter for stock plants are usually started up and repotted early in February to induce the abundant new growth that furnishes cuttings. The method of repotting will depend on the nature of the plant. Soft-wooded plants, like geraniums, are put in in the ordinary way and firmed with the fingers. The palms do best with the new soil more firmly packed about the old ball of roots. Hard-wooded plants with very fine roots, like the azaleas, should have the soil rammed down firmly about the old ball; for which purpose it is necessary to use a blunt, flat piece of wood, of convenient size. In repotting such plants, it is well to let the ball of roots soak several minutes in a pail of water before putting into the new pot. If very densely matted, make several holes in it with a spike, working it around, and leave the soil a little lower at the center of the pot to induce the water to run down through the root ball.

Plants that have been crocked in the old pots should have this material removed, if possible, before going into their new quarters.

Plants in large pots often use up all the plant food available, and where they cannot be given still larger pots become quite a problem. They are usually handsome specimens which one does not like to lose. Remove such a plant from its pot and carefully wash all the soil from the roots; clean the pot and carefully repot in fresh soil in the same pot. The result will be extremely satisfactory.

Until one has become proficient in the art of potting, it will pay well to practice with every plant and cutting that may be had. If you have mistakes to make, make them with these, so that your favorite plants may be handled safely.