What do the NPK numbers on a fertiliser bag actually mean?
Every fertiliser bag carries three numbers, such as 7-7-7 or 4-5-8, always in the same order: nitrogen (N), phosphorus (P), and potassium (K). Nitrogen drives leafy green growth, which is why a high-N feed suits lettuce and spinach. Phosphorus supports root and seedling development, useful when transplanting. Potassium builds flower and fruit quality, which is why tomato feed is typically high in K, something like 4-5-8, rather than balanced.
A balanced feed such as Growmore (7-7-7) suits general beds and allotment plots where you are not targeting one specific stage of growth. The numbers are percentages by weight, so a 7-7-7 bag contains 7% nitrogen, 7% phosphorus, and 7% potassium, with the rest being filler and trace elements. Working out how much actual nutrient you are applying from a bag of unfamiliar strength is where most gardeners guess wrong.
How much water do UK garden plants actually need?
Overwatering kills more container and greenhouse plants in the UK than drought does. Compacted, waterlogged compost starves roots of oxygen and encourages root rot, and the yellow, wilting leaves that follow look almost identical to the symptoms of underwatering, which leads gardeners to add even more water. Checking that the top few centimetres of soil are dry before watering again solves most of it.
Outdoor beds are a different problem. Southern and eastern England regularly see summer weeks with under 15mm of rain, well short of what a fruiting vegetable bed needs, while western and Scottish gardens rarely need supplemental watering outside a heatwave. Established shrubs and lawns usually cope on natural rainfall; it is young transplants, containers, and hanging baskets that need a real watering schedule, adjusted for pot size, plant type, and season.
Does planting by the moon actually make a difference?
Planting by the moon has a long history on British allotments: sow leafy crops during the waxing moon, root crops during the waning moon, and avoid sowing altogether around the new and full moon. Some biodynamic growers extend this into a full lunar and zodiac calendar.
The evidence is thin. Controlled trials looking for a lunar effect on germination or yield have mostly failed to find one, and the RHS does not endorse moon planting as a science-based technique. That said, the calendar still does something useful: it imposes a regular sowing rhythm, which on its own improves results compared with sowing whenever you happen to remember. Treat it as a helpful prompt rather than a rule, and keep your own sowing log to see whether it changes anything on your plot.
Which vegetables and herbs actually grow well together?
Some plant pairings genuinely help each other. Tomatoes and basil grown close together are a classic combination: basil is thought to repel whitefly and aphids, and the two share similar water and warmth needs, so they sit well together under glass or outdoors. Carrots and onions are another reliable pair: onion scent is thought to confuse carrot fly, while carrots do not compete with the onion's shallow roots.
Not every pairing works. Beans and onions inhibit each other's growth and should be kept in separate beds, and brassicas planted too close to strong-smelling alliums can struggle. Nasturtiums are worth growing near brassicas anyway, not because they help the cabbages directly, but because caterpillars prefer them, drawing pests away as a trap crop.