Mid June is a great time for plant growth, and left to their own devices, plants will do well enough at this time of year, however, if you want to have bumper crops of fruit, veg and flowers, you should be feeding on a weekly basis for the next couple of months.
What type of plant food you should be using depends on what you're feeding and how much time and effort you want to put into it.
Controlled release fertiliser. - If you are no good at remembering to feed your pots and planters, then
this is an excellent choice for you , as controlled release fertilisers break down when the compost is watered, (either by rain, or can or hosepipe) and supply a "ration" of feed over the season. Almost all shrubby plants grown on British nurseries will have a controlled release fertiliser in with the compost when you buy them. - These are often mistaken for slugs eggs, - but these pop if you squeeze them, slug eggs are soft and will just deform if squashed.
The most common brand of controlled release fertiliser is Osmocote, and it is sold in packs with a handy scoop to take the guesswork out of how much is needed. - my recommended choice for use when planting up hanging baskets.
Liquid fertiliser - this is the most direct way of getting food to the plants roots,- most liquid fertilisers can be diluted in watering cans, either from a concentrated liquid, or from granules or crystals, so that they can be watered on to the garden. Another way of applying liquid to the plants, particularly if you have a large area to do, is to use a hose end feeder. These have come on a long way from when I first used to get drenched as a trainee garden centre manager, and there is now a new system that uses a liquifeed screw in bottle to a hose end feeder. I've just entered a competition to try it out for free, - (1000 kits to be given away) if you want one too, just fill out a small questionnaire and enter the competition click here
Fertilisers that come into this category are numerous, but include worm leachate, Tomato food, Miraclegro, and Seaweed extract. If you have just a couple of pots to do, or a greenhouse of tomato plants to feed, I recommend using a liquid diluted in a watering can.
Granular fertiliser - this is great for lawns, and some feeding in borders (usually in the Autumn). In my experience granular feeds are the hardest to apply at the right application rate, and this can lead to scorching (overfeeding) which can leave foliage yellowing, and weak.
To ensure this doesn't happen, particularly when using a lawn feeder like the one in the photo, clean it out before using, and walk at a brisk pace, ensuring that you don't overdose at the end of each row as you turn.
I recommend using these on lawns that need a feed and weed, which are a reasonable size.
Now you know which type to use, there's no excuse, get out there and feed your garden, - i'm off to eat Strawberries grown fat on my worm food.