Flowers & companions
Nasturtium
Edible; aphid trap crop.
- Outside
- Direct after mid May
- Where
- Bed edges, poor soil
- Sun
- Full sun; takes light shade
- Water
- Soak in at sowing; then a finger test in dry spells
- Harvest
- Leaves and flowers, Jun to Oct
Care
- Water
- Soak the seeds in at sowing, then mostly leave it be; poke a finger down and only water in a genuine dry spell. Rich, wet ground and hot afternoon sun stress it more than drought ever will.
- Sow
- Big seeds, half to one inch deep since they need darkness to sprout, once the soil hits the mid 50s in May. Skip rows; tuck them where they can spill over a bed edge, then thin the crowd in place.
- Feed
- None, and that is not laziness. This is the one crop that wants poor ground, so leave the compost out of the hole and skip the liquid feed too; richer soil buys you leaves instead of flowers.
- Ready
- Pick young leaves and just-opened flowers whenever you want them; both head straight to the plate, since neither keeps once cut. Buds, green pods, and seeds are all fair game as well.
- Trouble
- Aphids mobbing a stem: that is the trap doing its job, so cut the stem off and bin it rather than reach for spray. Volunteers next spring: it self-sows, so thin or move the ones that land where you did not want them.
In a bag?
- Yes
- Up to a 3–5 gal bag.
- Water
- A bag dries far faster than the ground, so check every day or two in a hot spell and water until it runs from the base; even so, let the top dry before the next.
- Feed
- Still no feed, and use a lean mix over rich potting soil; a fed bag hands you trailing leaves and few flowers.
- Sow
- A few seeds per bag, set near the rim so they trail over the side.
Nasturtiums are the garden's decoys, edible flowers planted so the aphids gather somewhere convenient and expendable. They ask for poor soil and neglect, which is a rare bargain.
Growing
Direct sow the big seeds after mid May wherever the front of a bed or a low wall needs spilling over, and do not improve the soil; rich ground grows all leaves and no flowers. Settle the seeds in with one watering and leave the hose elsewhere for the rest of the summer; bloom runs June to frost. Station a few at the feet of the peppers and brassicas, and when a stem loads up with aphids, cut it and bin it, passengers included. That is the whole trap-crop protocol.
Varieties
Alaska carries variegated leaves worth growing on their own; Empress of India is the compact, dark-leaved classic.
In the kitchen
Leaves and flowers both eat peppery, like watercress with better looks. The green seed pods pickle into a fair imitation of capers.