Getting it to bloom

Why won't my Butternut squash bloom? (and how to make it flower)

Also called butternut pumpkin, gramma (Cucurbita moschata).

About Butternut squash

Cucurbita moschata · also called butternut pumpkin, gramma · edible

Butternut is a long-keeping winter squash with sweet orange flesh. More disease-resistant than C. pepo squashes, but slower to mature — needs 110-120 frost-free days. Direct-sow after last frost in rich soil. Pet-safe.

A cultivar of Cucurbita moschata, the moschata group was domesticated in the lowland tropical Americas (Mesoamerica) and is the most heat- and humidity-tolerant of the winter squashes.

Plant type: edible

Sources: plants.ces.ncsu.edu, extension.illinois.edu, en.wikipedia.org

The reasons butternut squash isn't blooming

Almost every non-blooming butternut squash traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
Heat or cold stress at flowering, or poor pollination, so flowers form but drop without setting.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding butternut squash a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get butternut squash to flower

Maximise sun. Give butternut squash the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Help it set. Keep moisture steady, avoid temperature extremes at flowering, and encourage pollinators (or hand-pollinate) so flowers turn into fruit.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for butternut squash and get the feeding right with the butternut squash fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Butternut squash flowers through its warm growing season and, with good pollination, follows each flush of flowers with the crop — expect a steady run rather than one burst.

Post-bloom care so it flowers again

Keep feeding and watering steadily so flowering and fruiting continue; remove tired or diseased growth to keep energy going into new flowers.

For everything else this plant needs day to day, see the full butternut squash care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Butternut squash blooming — frequently asked questions

Why won't my butternut squash flower?

Butternut squash flowers (and then fruits) on the current season's growth — it needs full sun, warmth, steady moisture and a switch to a lower-nitrogen, higher-potassium feed once it starts to flower. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make butternut squash bloom?

Give butternut squash the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does butternut squash normally bloom?