Learn which plants thrive in your Hardiness Zone with our new interactive map!

How to Grow Cotton Indoors

By Sarah Terry ; Updated September 21, 2017
Cotton plants
cotton field in contrast with blue sky image by lulu from Fotolia.com

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.


Things You Will Need

  • Cotton plant seeds
  • Peat pots, 3 inch wide
  • Planter pots, 12-inch diameter
  • Loam-based potting compost
  • Liquid plant or tomato fertilizer
  • Insecticidal soap (optional)


  • Turn the cotton plant pots about a quarter or half turn each day to ensure that the plants grow straight and not leaning in one direction toward the sunlight.


  • Watch out for the red spider mite on your indoor cotton plants. Treat a mite infestation by spraying the cotton plants with an insecticidal soap.

About the Author


Sarah Terry brings over 10 years of experience writing novels, business-to-business newsletters and a plethora of how-to articles. Terry has written articles and publications for a wide range of markets and subject matters, including Medicine & Health, Eli Financial, Dartnell Publications and Eli Journals.