When to feed a baby solids and what is best?

6 months. Years ago, breastfeading was frowned on & many made "formula" from boiled cow milk. Since cow milk is designed for calves, infants were fed early & often to make up for deficiences in cow milk. Now that breast is back, or formulas mimic breast, solids are optional. The sitting child is more capable of participating & few sit before 6m. Babies can wait past a year and thrive.Rice cereal to start.