Start by putting a tablespoon of puree made from only one vegetable in his/her milk. Mix finely, it should have a very smooth consistency and should, without being diluted, flow through the teat of a bottle. Little by little, increase the quantity of puree in the bottle; this can take a month to reach a real puree which you will then give by spoon.
Only introduce one new vegetable at a time, and another 48 hours after the first to check that there is no allergic reaction. As soon as two vegetables are tolerated, you can mix them together in the same puree.
Because baby has an acquired appetite for sweet foods, start introducing pureed fruit 2 weeks after the vegetables.
Finally, as from 6th month, you can introduce cereals by putting a teaspoon in a bottle.
Generally speaking, so that nutritional diversification goes smoothly, trust your baby. Your baby regulates himself/herself perfectly depending on his/her hunger: whether he/she has a big or small appetite, he/she will only eat what he/she needs.
The diversification will surely test your patience. You will have to accept that baby is growing up. Don't rush anything, listen to yourself and listen to your baby! Stay zen and breathe.
Make a real game of this stage and take this opportunity to educate baby by introducing new categories of objects and words. Name the vegetables and the colors, let him/her touch the foods… Everything is always easier when it's fun!
.You may feel overcome with this stream of information. What to feed baby, how to create his/her meals? Say to yourself that this basis should always be followed: majority milk + starchy foods + fruit/vegetables.
Example of a day's menu for a baby from 4 to 6 months: