Growth Rate

• When grown in ideal conditions, a croton stem or branch may add 1/4 to 6 inches of new growth in a 12-month period. The growth rate varies by cultivar. Large, more vigorous cultivars such as Petra or Mrs. Iceton may grow 4 to 6 inches a year, while a dwarf such as Picasso's Paintbrush only 1/4 to 1/2 inch in the same time frame. Rather than seeing growth merely as an increase in stem length, growth in crotons also manifests as budding side branches with more leaves.
  
  

Encouraging Growth

• As tropical plants, crotons grow more robustly in warm to hot temperatures with a fertile, evenly moist soil and with high humidity. When grown outdoors in tropical regions or indoors in a bright greenhouse, growth may occur year round, but most profoundly from March to October. The cooler air and soil temperatures and lack of rainfall in the tropical winter causes growth to halt. As a houseplant, crotons experience lower humidity and limited sunlight, and therefore grow mainly from late spring to late summer when the house is warmest and days long and sun rays the most intense.
  
  

Soil Fertility

• Grow crotons in acidic or neutral pH soil that is evenly moist but well-drained. Sandy soils enriched with organic matter are ideal. Impoverished sandy soil is not only too dry for crotons, but the lack of nutrients stresses the plants and impedes any growth. Infertile and highly alkaline garden soils cause nutrient deficiencies. No growth, very slow growth or malformed or sallow-colored new leaves occur when a croton plant does not grow in a fertile soil.
  
  

Using Fertilizer

• Don't fertilize crotons from fall to early spring when they naturally aren't growing fast because of cooler weather and shorter days with low intensity sunlight. The most important thing for crotons in winter is protection from frosts and receiving as much direct sun as possible to prevent abortion of leaves. Slow-release granular fertilizers supply nutrients over a long period and mulching the soil provides nutrients, too. Liquid fertilizers are practical only when growing crotons in containers. Focus fertilizing of crotons from mid-spring to early fall, when they naturally grow the most. This practice will maximize the growth rate potential.