TOO HIGH A TEMPERATUREWhen plants are grown in an unusually high temperature, with moisture, the growth is forced, and, being soft, is easily injured. A strong draught, even if only l0 degrees or 20 degrees cooler than the surrounding air, will seriously chill plants in this condition. The result will be that plants like the geranium and heliotrope will turn yellow and drop their leaves; with palms, the tips of the leaves will turn brown. To get the plants back into proper condition will take months of careful attention, and in the case of palms or ferns it will take a year — preferably at the florist's. To give the atmosphere the proper amount of moisture have a small dish on the radiator, register, or stove, and keep it full of water.
WATERINGThe second most exacting requirement of plants is watering. Too much water will make the soil sour; with too little water the plant will wilt. The effect of either will be yellowing and dropping of the leaves. It is easier, however, to drown a plant than to kill it by drought. No hard and fast rule for watering can be made. Plants may need water twice a day or only once in two days. The best way to determine whether a plant is dry is to rap the pot sharply with the knuckles of the hand. A hollow, or ringing sound shows that the soil needs water; a heavy, dull sound indicates that it has sufficient moisture. Usually you can tell whether the soil needs watering by looking at the surface. If it is dry and powdery give water.
If by any chance the ball of earth should become very dry, plunge it in a pale full of water and let it stand five or ten minutes — until the whole ball is soaked through. When the air-bubbles cease to rise the ball is generally thoroughly soaked. Pouring water on the top of the soil of a dried-out pot plant is generally useless because the ball contracts in drying and leaves a small space between itself and the pot down which the water will run.