Start adding Monster Silicate (potassium silicate) in the last week of Veg and use until at least week 5 or 6 of Flower to help beef up the stocks and stems, plus it helps strengthen and protect the plants.

Use it at about 0.25 ml (1/4 tsp) per litre or 1 ml (one eyedropper) /1 tsp per 4 litres weekly. It will raise the pH so just watch that and adjust accordingly.