Feed the plants
Most composts for containers and baskets contain limited amounts of food. Within four to six weeks of planting, fast-growing, hungry bedding plants will have depleted most of the goodness in the compost. So, you’ll need to add more nutrients to improve your plants’ flowering performance and encourage stronger growth. Make sure your feed contains plenty of potassium, which boosts flower growth and is a key ingredient in tomato fertiliser. Follow the instructions and mix feed into one watering per week in summer.
Another and easier way to be sure your plants never go short of food is to add slow-release fertiliser to your compost. Mix granules of feed, often combined with water-retaining gel, into the compost at planting time. Alternatively, use pellets of slow-release fertiliser granules, pushing these down into the compost. As you water your pots from above, the resin coating of the granules slowly dissolves to release feed into the surrounding compost. This is a gradual process because the granules are designed to release fertiliser slowly over many months.