Fertilising guide

How to fertilise Turnip 'Purple Top White Globe' (Brassica rapa var. rapa 'Purple Top White Globe')— schedule & NPK

Also called Purple Top White Globe turnip, garden turnip.

More about turnip 'purple top white globe'

About Turnip 'Purple Top White Globe'

Brassica rapa var. rapa 'Purple Top White Globe' · also called Purple Top White Globe turnip, garden turnip · edible

'Purple Top White Globe' is the classic heirloom turnip with smooth white roots flushed bright purple at the shoulder. Fast and reliable, roots reach 8-12 cm and mature in about 50-55 days, sweetening after frost. Both the root and the nutritious greens are eaten. Sow direct in full sun in cool spring or autumn weather.

Growth habit: Biennial grown as an annual; a rosette of bristly green leaves above a swollen, flattened-globe root sitting at the soil surface.

What fertiliser turnip 'purple top white globe' actually wants — and why

Turnip 'Purple Top White Globe' stores its crop underground, so the rule is the reverse of leafy plants — go easy on nitrogen, which sends energy into tops at the expense of roots.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for turnip 'purple top white globe': match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed turnip 'purple top white globe', and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For turnip 'purple top white globe':

Moderate feeder. Incorporate compost before sowing; a balanced or slightly nitrogen-leaning feed early on supports leaf and root growth. Avoid excess nitrogen late, which favours tops over root quality. In practice: prepare the bed with well-rotted compost (not fresh manure), then little or no extra feeding through the season (spring through early autumn); a light potassium feed mid-growth at most.

The dormant-season rule matters more than the exact interval: skip feeding entirely when turnip 'purple top white globe' is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for turnip 'purple top white globe'

Less is more for turnip 'purple top white globe'. If you feed at all, keep it light and low-nitrogen — the soil preparation does the work, and over-feeding actively spoils the crop.

Feeding always goes onto already-damp soil, never dry roots — water turnip 'purple top white globe' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the turnip 'purple top white globe' watering schedule.

Signs you are over-feeding turnip 'purple top white globe'

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for turnip 'purple top white globe':

Large lush leafy tops and small, forked or hairy roots.
Split or cracked roots from a nitrogen-and-water surge.
All foliage and no usable crop at harvest.

Signs you are under-feeding turnip 'purple top white globe'

Genuinely uncommon in reasonable soil — these are not hungry plants.
Pale, weak tops and small roots only in very poor, exhausted ground.
Slow growth across the whole bed in long-uncultivated soil.

If the symptoms point at watering, light or roots rather than nutrition, the full turnip 'purple top white globe' care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flushing is not the issue for turnip 'purple top white globe' — the equivalent care is avoiding fresh manure and high-N feeds entirely, and rotating beds so the soil is not over-rich from a previous hungry crop.

Organic vs synthetic feeds for turnip 'purple top white globe'

Organic options

Well-rotted compost worked in the season before, or for a previous crop, is ideal — never fresh manure. UK: garden compost, low-N blends; US: Espoma Garden-tone sparingly or finished compost. Lean and well-worked beats rich.

Synthetic / liquid feeds

If anything, a low-nitrogen, potassium-leaning feed only — UK: a high-potash feed mid-season at most, never a general high-N; US: a 5-10-10 sparingly. Most root crops crop best with no synthetic feed at all.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising turnip 'purple top white globe' — frequently asked questions

What fertiliser does turnip 'purple top white globe' need?

Low-nitrogen, with modest phosphorus and potassium for root development — ideally compost-improved soil rather than a high-N feed. Excess nitrogen forks the roots and grows lush tops instead of a crop. Turnip 'Purple Top White Globe' stores its crop underground, so the rule is the reverse of leafy plants — go easy on nitrogen, which sends energy into tops at the expense of roots.

How often should I feed turnip 'purple top white globe'?

Moderate feeder. Incorporate compost before sowing; a balanced or slightly nitrogen-leaning feed early on supports leaf and root growth. Avoid excess nitrogen late, which favours tops over root quality. Moderate feeder. Incorporate compost before sowing; a balanced or slightly nitrogen-leaning feed early on supports leaf and root growth. Avoid excess nitrogen late, which favours tops over root quality. In practice: prepare the bed with well-rotted compost (not fresh manure), then little or no extra feeding through the season (spring through early autumn); a light potassium feed mid-growth at most.

What strength of feed for turnip 'purple top white globe'?