Botrytis (grey mould) on strawberries

Hi all, I'm new here and thought I had already posted this but cannot find it. Sorry if I am a nuisance.

I bought raised beds to grow strawberries in, and all new plants, this year. They were looking fantastic till they started to fruit and then most of the fruit became covered in grey mould. At first I just thought it was bad luck and only affected a few berries but after some weeks I have decided it is botrytis. I read that this is notoriously hard to treat and usually means the plants must be destroyed. I am heartbroken. I don't have this fungus on any other fruit or veg

I am in the process of cutting them all down to leave just the crowns, but is there anything I can treat them with?

Might they recover or should I ditch them up and start again with new plants? What about the few plants that haven't shown signs of the disease?

Can I use the runners?

Do I have to replace the compost they are in?

Should I give up trying to grow strawberries?

Hope folks can help me.

Meg

 

Hi Meg ... and welcome.

I'm afraid I have no idea how to grow strawberries, but there will definitely be people here who can help, so hang about till they arrive.

My only thought would be it has been a very wet summer (I assume you are in the UK), which encourages all sorts of mould-type problems, so don't despair just yet.

 

I've never had it on strawbs, but I think it's an airflow problem that initially causes it - damp and humid, which the spores like.
How are you growing them @Mad Meg - are they very congested in the beds? The size of those will dictate the number you have in each one. I mostly grew mine in containers or the odd one or two in my raised beds, but it's important they have enough room. Slugs were too big a problem for growing them all in a dedicated bed, hence the pots.
If they were staying long term in the beds, it's also important to use a soil based medium rather than just compost, as that isn't hearty enough other than for just a season.

 

I knew someone would know something. I dabbled with alpine strawberries one yr, as I was given the seeds as part of a gift with a tiny pot and a pouch of compost, both utterly inadequate for their needs. Anyway, I got proper sized pots to plant them in and they did produce fruit, but it was fairly tasteless, so I didn't bother again.

And that is pretty much the totality of my fruit and veg gardening adventures, except for collecting very sour cherries from a tree.

 

I used to grow in containers but it was difficult to keep them moist in the summer and the yields were poor. I filled the raised beds with compost as per the instructions on the raised beds but they would only be in compost if they were in pots. I've no problem with slugs or snails really. I do think they are too close together so can thin them out.

But I really need some help on the effects of the botrytis.

 

Botrytis is a fungal disease that is usually brought about by a damp atmosphere, there used to be fungal sprays that worked against it but these days I think most have been banned.

Its probably getting a bit late now for strawberries that are not under cover, depending on where you are.

A good air flow is probably all you can do.
Its a fungus that is always there, but only really causes problems when the conditions are right for it to grow.

 

The airflow definitely sounds like the main reason. Congestion is likely to be the cause of that. How many have you got though, and what size is the container?
For example, in a 15 inch diameter pot, I'd have no more than 2 or 3 plants, and they'd be moved once they were more mature, and that would be in their 2nd or 3rd year.

 

They are in raised wooden beds 48 ins x 30 ins and abt 8 ins deep compost including added perlite and vermiculate. Also chicken manure early on. The beds are lined with black polythene that is breathable (it has tiny manufactured holes in it) and drainage seems good. I water with a dripper system so not overhead at all except when adding feed. There are 24 plants per bed so 60 sq ins each. That seems similar to yours in the first year. They are in full sun - when there is any!!! It has been a cool damp year really.

Will spacing them out mean I don't need to throw them all away or will there be spores in the soil or in the crown waiting to strike again next year?

 

The botrytis spores are always in the air but only cause problems when conditions are right, as @fairygirl says.
Unfortunately, it sounds like your setup is restricting airflow to individual plants, so all you can do is thin them out. I used to plant them about 18" apart, if that helps?

 

Wow BobTG mine are much closer than that, so I will thin them out drastically. Fingers crossed for next year, cos the few OK strawbs were lovely!!!

 

In open ground, or a dedicated bed, I'd probably have them around a foot apart, but it can also depend on the variety and how big they get through the season. 24 plants in a bed that size is a huge amount
They benefit from rich soil and some food, and certainly like decent amounts of water, which isn't a problem where I am, but the soil mix needs to be hearty too. We don't get the type of heat and humidity here either, which is probably why I've never had the problem. The better the plants grow, the more foliage they have, so the bigger chance of being crowded.
Growing in a pot is different from an open bed though, simply because there's fewer plants in that given area, whereas in a bed there's a lot more foliage close by each plant - a denser area altogether. Pots can be put in a more open setting with no, or very few plants nearby.
If you have some pots, you could thin them and plant some up in the pots for next year.

 

I started off with everything in pots but tbh drying out was a problem so I built raised beds on open ground so the bigger veg go in there and can be rotated. Also easy to add nutrients to the soil each year. I don't want to use one of these beds for strawbs, hence the new smaller wooden beds.

Any suggestions what to add each year to keep the soil good?

 

I wouldn't have added Perlite and Vermiculite to your mix for a raised bed. They're mainly used for growing seed or small cuttings as they provide really sharp drainage for those. If you want to ensure good drainage, grit or even pea gravel is better, and far cheaper, but ideally it's a soil based mix you'd use for a raised bed, which will suit most plants, and the addition of some compost each year [and that grit if it's a very wet, open site] will do the job. As you mention pots drying out, it sounds like you need a heftier mix rather than a more free draining one anyway.
For greedy plants like strawbs, you can add rotted manure as an extra, but it's better done at the time of filling, although you can add the odd layer in late winter/early spring when plants are about to start growing. Alternatively, some slow release food in spring, or tomato food for applying in the main season.
Strawbs need to be grown in roughly 3 year cycles though - so you'd need to plan for that. Do you have more than one bed for them? They tend to be less productive after 3 or 4 years, so it pays to take runners each year and grow them on to eventually take the place of the original plants. They grow on in their first full year, then you'd start taking fruits in the following year, while letting them become bigger. They're at their best when about 2 to 3 years old, in terms of production.

 

Fairygirl, thank you for all this advice - some of which I have learnt the hard way over the past few years of growing, but still lots to learn. I will incorporate some heaftier soil when I have thinned out the plants. I have already cut off most of this year's runners as a precaution cos of the botrytis but as all my plants are only one year old I will not need them next year.

 

No probs @Mad Meg. I hope things improve for you next year with them.
The runners are best removed on such young plants, so that's the right thing to do.
It's always a learning curve isn't it? Raised beds are really useful for me as the soil is heavy clay, but they drain more quickly, so again - if you have a drier climate, a heftier mix will be better for strawbs as long as it isn't permanently soggy. It's easier here for strawbs because our climate is also less inclined to have that heat and humidity. The airflow is certainly the most likely cause of the problem, so giving them a bit more room should help.

I think the variety makes a difference too. I've only tended to grow Elsanta, largely because my sister gave me some when I had my first proper garden, and they're a very reliable variety. They were great when my girls were small, and I hoped it would encourage them to be outside and have an interest in gardening. That didn't happen! Such is life.

I don't really like strawbs that much, prefer raspberries, so I've now just plonked most of the ones I had into the front garden, in borders with all sorts of other stuff, and the wildlife gets the benefit.