Buzz Off: Sciarid Fly Nematodes

Last year I started overwintering plants in style – or at least in quantity. As I discussed in Overwintering Tea, Coffee and Other Tender Edible Perennials a couple of weeks ago, this year there were even more tender plants knocking on the door once autumn’s hoary fingers reached our garden. I did seriously consider whether or not to overwinter chillies this year, but my tree chillies only started to fruit last week and with so many other tender plants to bring in, I decided to choose a selection of chillies to bring in as well.


My first rocoto tree chilli – ‘Albertos locoto’

Two Sticky Issues – Greenfly and Sciarid Flies

I had a problem with greenfly in early spring last year and never really found a successful way to deal with this problem, so I’m not looking forward to a repeat of the sticky insect invasion this year. Any ideas on ways to deal with this would be most gratefully received. (I did use organic sprays and sticky traps to try and control them). But the main problem I had initially was with sciarid flies or fungus gnats. These are often also a problem with house plants – especially when the compost is high in organic matter like the green waste in the peat-free compost I currently use. (I have used other peat-free compost like the superb Dalefoot wool compost, especially in spring when I’m bringing a lot of seedlings into the house, but can’t stretch the budget to afford it for all my plants at the moment. Besides which, the plants often get infested with sciarid flies in the greenhouse in the summer anyway.) The sciarid fly larval stage can attack the roots of plants, but my main issue with them is the annoying clouds of flies in the house over winter. Conventional tricks to avoid them are to avoid overwatering and water from beneath, but I didn’t find this helped much. I also tried covering the compost with gravel, but this had very little impact on fly numbers.


Return of my little ‘friends’…

Biological Control

So last year I tried nematodes (microscopic worms) as a way of controlling the flies. I’ve previously used nematodes outside very successfully to control pests like vine weevil in pots, but had never tried them in the house. The nematodes worked in about a week and my plants were fungus gnat free for the rest of the autumn and winter. As long as no other plants are introduced into the house with fungus gnats to re-infest cleared pots, this should be a one off treatment each autumn. This year I was sent a free pack of nematodes to trial by The Green Gardener and I treated my plants at the end of last week.


First tray of plants in the bath ready for nematode treatment – bit like sheep dipping

It doesn’t take long to apply (unless you drop a tray of cacti on the floor like I did and thus need to get the vacuum cleaner and cloths out…) The compost needs to be moist before application and the house above 10ºc, with pots out of direct sunlight. One pack (costing £12.50) treats up to 15 sqm of compost – far more than I needed even for 5 full trays of plants, but the solution with the nematodes in can’t be made too strong, so as long as there isn’t more than 15sgm to treat, one pack is ideal.


Small pack – big results

Once again, my pots were cleared of flies within the week and I hope to keep them that way until it’s time for the plants to return to their summer homes. Now I just need to crack the greenfly issue and I’ll have this overwintering lark sorted…

If you’d like to try nematodes to keep sciarid flies off your houseplants, the product can be found on here on The Green Gardener’s website…

Product Reviews

Just a note on product reviews on the blog – I’ve discussed many plants and products over the past few months which have not been free trials. Any reviews of free products or plants will always be a reflection of my honest experiences, good or bad. I don’t review anything which I don’t consider to be of use to my readers and only choose products which I already use and find helpful, or those which I want to try as part of my ongoing garden and allotment development. I will always make it clear where a product has been sent free for me to trial and I hope that the reviews will be useful for other gardeners.

If you’d like to follow the blog, you can do so below and do leave me a comment – especially if you know of any good ways to get rid of indoor greenfly.  🙂

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Overwintering Tea, Coffee and Other Tender Edible Perennials

I bought a tea plant (Camellia sinensis) and a coffee plant (Coffea arabica) earlier this year. I’m hoping, in time, to be able to produce infinitesimally small amounts of low quality hot beverages with which to underwhelm my friends and family. In the meantime, the coffee needs to come in for the winter and I’ll probably bring the camellia in too, although in time it should become large enough to overwinter successfully outside in its pot. Planting it in the ground here isn’t feasible as our soil is alkaline (pH 7.5) and camellias need acid soil. But potted in ericaceous compost, it should exist quite happily and produce leaves for green tea and salads for many years to come.

The list of plants needing winter attention is growing as my plant collection becomes more extensive and unusual, so this year I’m not convinced it’s all going to fit. Time to clear greenhouse benches and indoor windowsills, squeeze plants onto trays and cross my fingers as chillies, tea, coffee, lemongrass, lemon verbena, Vietnamese coriander, yacon, cucamelons and inca berries all come in for the winter…


Scrubbing away a year’s grime

Fungus Gnats

My overwintering regime comes from a mixture of experience, good advice from fellow growers and intuition (aka. guesswork). Once the pots are in I’ll be treating them with nematodes as I had real problems with fungus gnats in the house last year (the annoying little black flies which buzz around the compost and can multiply disturbingly in just a few days) and using nematodes completely cleared them up. I’ve been sent a free trial pack of nematodes from the Green Gardener which can be stored in the fridge in their sealed packet for a few weeks until needed and then simply watered in the specified concentrations onto moist compost. I’ll be using them in the next few days and will report back on how successful they are this year. Here’s to a fly-free winter and lots of happy hibernating plants ready to burst into life early next spring  🙂


My nematodes – currently residing in the fridge


My 39 chilli plants will not, alas, all fit in the house, so the challenge has been to decide which are keepers and which will be feeding Compo (the compost heap). I’ve saved lots of seed that I will be able to sow next January and I’ve been sent an amazing array of exciting varieties by a reader of my blog who grows an extensive range and has been very generous in our seed swap. There is now no hope for me – I’m a confirmed chilli addict. Thirteen varieties this year and I suspect it will only get worse in 2017…

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The crazy chilli collection 2016!

As well as saving seeds, the kitchen has turned into a pickling factory with shallots, red onions and chillies disappearing into jars, to reappear in a few weeks to jazz up pizzas, sandwiches and salads.


Pickled chillies to heat up cold winter suppers

Cucamelons and Yacon

I’ve tried to overwinter cucamelon (Melothria scabra) tubers a couple of times and never been successful. They’ve been left them in pots in the unheated greenhouse and brought in as dried tubers, but each winter rot has set in. This time I’m going to attempt to keep them in their pots, dry on a windowsill alongside the yacon (Smallanthus sonchifolius) and see what happens…

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I’m hoping for an early harvest next year – if I can only manage to overwinter the tubers…



The lemongrass (Cymbopogon citratus) overwintered well last year and then I lost nearly all my plants by putting them out in the unheated greenhouse too early. Second year plants definitely grow more strongly (providing they’re kept warm), whereas first year plants don’t really have long enough to develop and multiply. So I’m intending to learn from my mistake and keep them indoors next spring until the frosts have well and truly finished.


These little guys never really developed into mature plants

Lemon Verbena

I’ve had the same lemon verbena (Aloysia citrodora) plant for 5 years. It dies back in winter in the unheated greenhouse and reappears in spring, usually just after I’ve given up hope – I should know better by now. This year I repotted it and put it outside during the summer. It rewarded me by producing more leaves than we could use. It is such a lovely plant. Unlike lemon balm (Melissa officinalis), which has a similarly enticing scent, I find lemon verbena transfers its sherberty aroma more successfully to hot and cold drinks, cakes and spicy curries.


The lemongrass stirring from its winter slumbers

This year I’ve dried the remaining leaves for tea over winter and I’m going to have another go at propagating from cuttings next year (something at which I have an embarrassingly bad track record).


Makes the best tea mixed with Moroccan mint

Vietnamese Coriander

A new herb for us this year, I’ve been impressed with the easy of use and clean taste of our Vietnamese coriander (Persicaria odorata). I love the more traditional coriander (Coriandrum sativum), but the necessity of repeated sowings to cater for the speed at which it bolts is an extra job in a busy summer schedule. If the Vietnamese coriander overwinters successfully, it will allow a continuous supply of tasty leaves for cooking throughout the summer and autumn months and will have earned its place in the herb container garden.

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Vietnamese coriander – so far, so good

Inca Berries

A couple of weeks ago I was lamenting the three worst crops of 2016 – inca berries (Physalis peruviana) being one. I had an extremely helpful comment about the perennial nature of the plant and therefore the possibility of overwintering it. I have tried growing physalis for 4 years now, with very minimal harvests, so had already discounted new plants in 2017. However, I’m going to try bringing a couple of plants indoors to see if they produce higher yields in their second year. If not, they’re history – at least until I move on to warmer climes.


My inca berry harvest

I’d love to know if anyone else is growing tea or coffee, and what the verdict is. And does anyone else contemplate paying their friends and relatives to overwinter plants on their windowsills due to a mismatch between plant collection ambitions and house size? Or is that just me?! Do leave me a comment below to let me know what other overwintering activities are going on this autumn…


Assembled plants for overwintering – maybe we should move out?


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