6 Months: Solid Foods Are Starting, and the Peanut Window Just Opened

Month six is when everything accelerates. Sitting up. Rolling consistently. Babbling with real intent. Object permanence beginning to click. But the biggest milestone this month isn't physical — it's nutritional.

Solid food introduction opens a window that has real consequences if you get the timing wrong in either direction. And there's a second window that most parents still don't know about, with a deadline that closes at 11 months.

Starting Solids — Readiness, Timing, and What Actually Matters

Starting solids is about developmental readiness, not a date on the calendar. Most babies are ready around 6 months. Starting too early — before 4 months — is linked to obesity and digestive problems. Starting too late — after 7 months — increases the risk of iron deficiency and texture aversion, which is a primary driver of picky eating in toddlers.

The Three Readiness Signs

All three should be present before you start:

• Sitting with minimal support and good head control — A baby who can't hold their head up isn't safe to swallow semi-solid food.
• Loss of the tongue thrust reflex — The automatic pushing-things-out-with-the-tongue that protects newborns. When it's gone, they stop ejecting the spoon.
• Showing interest in food — Reaching for your plate, watching you eat, leaning forward when food is nearby.

What to Start With

Single-ingredient smooth purees. The goal of first foods is exposure and safety — introducing one ingredient at a time lets you identify any reactions before mixing. Good first foods: sweet potato, avocado, peas, pureed chicken, pureed beef. Introduce one new food every 3–4 days and watch for rashes, vomiting, or diarrhea.

Iron is the critical nutrient right now. Your baby's iron stores from birth are nearly gone at 6 months. Breast milk doesn't supply enough to replace them. Iron deficiency in the first year affects brain development, cognitive function, and behavior. Prioritize iron-rich first foods: pureed meats (beef, chicken, turkey) and iron-fortified oat or barley cereal.

Avoid making rice cereal your primary first food — it's low in nutrients and has arsenic concerns. Fruits and vegetables are fine but shouldn't crowd out iron sources in the early weeks.

With First Son, I started with rice cereal because that's what everyone said to do. I didn't know about iron. I didn't know about texture windows. I thought I was doing the right thing. With Second Son, I started with pureed beef. Different starting point. Different trajectory.

The Peanut Introduction Window — This Changed Everything

This is one of the most important things in this entire guide, and most parents still don't know it.

In 2015, the LEAP study — published in the New England Journal of Medicine — showed that introducing peanuts between 4 and 11 months reduces the risk of peanut allergy by up to 80%. The old advice was to avoid peanuts. The new guidance is the opposite: introduce them early, and keep offering them regularly.

The window closes at 11 months. Miss it, and the protective effect is gone.

If your child has no eczema and no known food allergies: introduce at home, no doctor visit needed. Mix 1/4 teaspoon of smooth peanut butter into fruit or vegetable puree. Offer a small amount on a spoon. Wait 20 minutes. Watch for reactions: hives, swelling, vomiting, difficulty breathing. If no reaction, offer peanut products three times per week to maintain tolerance.

If your child has mild to moderate eczema: ask your pediatrician first — they may recommend an allergy test before home introduction.

The same early-introduction principle applies to eggs, tree nuts, fish, and wheat. Introduce them during this solid food window — ideally before 9 months — using the same single-food, watch-for-reactions protocol.

Motor Milestones at 6 Months

• Sitting with support — Most babies sit propped or with minimal support at 6 months. Sitting independently — no hands — typically develops between 6 and 8 months. If your baby is not sitting independently by 8 months, mention it at the next well-child visit.
• Rolling both ways — Most babies roll front to back around 4 months, then back to front around 5–6 months. By 6 months, rolling in both directions should be established or emerging.
• Hand-to-hand transfer — Your baby can take an object in one hand and deliberately pass it to the other. This is a significant fine motor and cognitive coordination milestone.
• Bearing weight on legs — When held in standing position, your baby pushes down and bears weight. Normal exploration — building the muscle memory they'll need later.

Cognitive Milestones at 6 Months

Object Permanence — Beginning

Object permanence — the understanding that things continue to exist when you can't see them — starts emerging around 6 months. This is why peek-a-boo is suddenly funny: your baby is genuinely surprised that you disappeared and then appeared again.

As object permanence develops over the next few months, it will drive two things: increased separation anxiety (they now know you exist even when you're not in the room) and more deliberate searching for hidden objects.

Recognizing Their Name

By 6 months, most babies are beginning to turn toward the sound of their own name. Reliable, consistent name response should be established by 7 months. If your baby isn't responding to their name at all by 7 months, mention it at the next visit — it's a flag for both hearing and social development.

Language Milestones at 6 Months

Babbling should now be well established — consonant-vowel combinations like "ba ba," "da da," "ma ma" with clear intent to communicate. Your baby is also varying tone to signal different emotional states.

Keep up the conversational turns: respond to their babbling, pause, let them respond. Research links high-volume early parent-child conversation directly to vocabulary size at age 3.

No babbling by 6 months is one of the earliest and most consistent language red flags in the research. Mention it at the 6-month visit. Don't wait.

The 6-Month Well-Child Visit

This is a major visit. Your pediatrician will assess sitting, babbling, hand-to-hand transfer, and early object permanence. It's also the green light for solid food introduction if you haven't started.

Vaccines at this visit: DTaP (dose 3), Hib (dose 3), PCV (dose 3), polio (dose 3), hepatitis B (dose 3), influenza (first dose — requires a second dose 4 weeks later if it's their first flu vaccine ever).

Questions worth asking: the peanut introduction protocol specific to your baby's history, whether to introduce in the office or at home, and what iron-rich foods to prioritize first.

What to Do Right Now

1. Introduce peanuts this week. Mix 1/4 teaspoon smooth peanut butter into a puree. Wait 20 minutes after the first taste. Watch for reactions. If none, offer peanut products three times per week. The window closes at 11 months.
2. Start with iron-rich first foods. Pureed beef, chicken, or turkey. Iron-fortified oat or barley cereal. Iron stores are depleted at 6 months and breast milk won't replenish them fast enough. This is not optional.
3. Introduce one new food every 3–4 days. Single ingredients only at first. You need to identify any reactions before mixing foods. Move through the allergens — eggs, fish, tree nuts, wheat — during this window.

Month seven is when the texture window opens for real. You want solids well established before that arrives.

Frequently Asked Questions