27 October 2026

Is it warm enough to use nematodes?

We are asked a lot at this time of year (and in the Spring) whether it is OK to use nematodes? The answer is that it depends on the soil temperature. Nematodes are microscopic worms that are used to control a range of pests and they have a temperature at which they are active, so how late / early in the season you can use them depends on the weather. Below you will find the minimum temperature for using our nematodes, but this is the DAYTIME temperature needed and it does no matter if it drop below this at night i.e. if the Leatherjacket Killer nematode needs a temperature of 10c, as long as the daytime temperature is 10c or above, it is still OK to apply even if it drops below this at night – the nematodes will simply become incative at night (they wont die) and will start working when the temps rise the next day. 

Nematode temperatures guide :-

Nemasys Vine Weevil Killer – Needs a DAYTIME soil temperature of 5c, so it is normally used under-glass / indoors ALL YEAR ROUND or outdoors between March and November. We use a low temperature nematode which means our treatment only needs a daytime soil temp of 5c, so it can be used much later / earlier in the season than some other treatments. Use it to control vine weevil grubs in the Spring and in the Autumn when the vine weevil grubs are active. Use it in the spring around March / April and then again in the autumn normally between Sept – Nov. 

EasyNem Slug Nematodes – Needs a DAYTIME soil temperature of 5c, so it is normally used under-glass / indoors ALL YEAR ROUND or outdoors between March and November. Use it to control slugs throughout the growing season i.e. apply every 6 weeks between March and November BUT application as early and as late as possible in the season to control the breeding slugs before they so too much damage is recommended.

Nemasys Leatherjacket Killer – Needs a DAYTIME soil temperature of 10c. Used to control leatherjackets in the Spring (apply at double strength) and in the Autumn when the leatherjackets are active – these are the most effective time to treat as the pest is active, close to the surface and the soil is normally warm enough. Use it in the spring around March / April and then again in the autumn normally between Sept – Nov. 

Green Gardener Chafer Grub Nematodes – Needs a DAYTIME soil temperature of 12c. Used to control chafer grubs in the Spring and Autumn when the grubs are active – these are the most effective time to treat as the pest is active, close to the surface and the soil is normally warm enough. Use it in the spring around April and then again in the autumn normally between Sept – October. 

Green Gardener Fruit and Veg Nematodes – Needs a DAYTIME soil temperature of 12c. This mixture of nematodes is used to control a range of pests including Box Tree Caterpillar, Caterpillars, Lawn Fleas, Codling Moth, Ermine Moth and Frit Fly. Used from spring i.e. April onwards until the autumn normally between Sept – October. Apply when the pest is present. 

Nemasys No Ant – Needs a DAYTIME soil temperature of 10c. Used to control ants in the lawn from spring i.e. April onwards until the autumn normally between Sept – October. Apply when the ants is present and ant hills are appearing on the lawn surface. 

Soil Thermometer – If in doubt, use a soil thermometer to check the daytime soil temperature and as long as it is warm enough then it does not matter what time of year it is i.e. certain parts of the country stay much warmer than others, so it maybe you can treat much later / earlier in the season than omeone else in another area. To be sure, take the soil temperature if you are treating early / late in the season. Special Offer – normally £12.99 NOW £9.99 while stocks last.

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