Cotton is a perennial tropical plant that produces cotton bolls that are used to make clothing and other textile goods. Cotton plants enjoy sunny and warm conditions, requiring four to five months of frost-free temperatures to mature. Because many regions don't have climates like this, growing cotton plants indoors is a great option. You can not only greatly extend your growing season for the cotton plants, but you can also better protect the plants from damaging winds and heavy rains.
Plant the cotton seeds in 3-inch-wide peat pots in groups of two or three seeds. Plant the seeds about ½ to 1 inch deep into the peat pots.
Set the peat pots in a sunny, south-facing window and keep the seeds warmed to about 65 to 68 degrees Fahrenheit. Water the peat pots lightly every other day to keep the seeds slightly damp at all times.
Thin out the weaker seedlings in each peat pot after the cotton plant seeds germinate and begin to sprout. Allow one strong, healthy cotton seedling to remain in each pot.
Transfer the cotton plant seedlings into 12-inch-diameter planter pots when their roots begin to outgrow the peat pots. Fill the planter pots with a loam-based potting compost mixture, not one that's peat-based.
Place the cotton plants outdoors in full sun during days when temperatures are well above 65 degrees and there's no heavy rain. Bring the plants indoors and place them in a sunny window when temperatures are cooler.
Feed your cotton plants once each week with a liquid plant fertilizer that's high in potash (potassium) or one designed for tomato plants. Follow the fertilizer dosage instructions on the label.
Water the seedling and mature cotton plants two or three times per week to soak the soil around the roots, allowing the top layer of potting mixture to dry slightly between waterings.