A Gardener's Weather Diary: May 2019

Thursday 30 May 2019

Proper Day's Rain Wanted

It seems quite a while ago now since we had what I would call a proper wet day. The forecast for the last week or so has been correct in predicting showers. The trouble is by their nature they're hit and miss and I think in general we've been pretty good at doing the missing.

Temperature & Rainfall Records 30 April - 30 May 2019

I've set the rainfall axis to 50mm or about 2in as this is around average for May so we should have a full column of blue adding up the month's rainfall. Currently the total stands at 35.0mm (1.4in), which doesn't sound too bad but most of that has fallen in amounts that do nothing but wet the top of the ground before evaporating away.

The table below shows the amount of rainfall we've had in the previous 12 months at the end of each month from January 2011 to May 2019. We'd expect around 600mm (24 in) over the year but at the moment it stands at just over 400mm (16in) and we're experiencing one of the drier periods of the last 10 years.

At the plot on Tuesday afternoon what looked like a heavy shower passed close by the allotment.

Of course close by isn't good enough and the allotment is dry and would benefit greatly from either a good downpour or a steady day's rain. Whilst a sprinkling from a shower doesn't do much in the way of watering the allotment it does keep the surface moist enough for slugs and snails to go on marauding night time raids. They'd managed to find our newly planted brassicas.

Savoy cabbage - Sabrosa

Cabbage - Red Lodero

The forecast is for more showers and some rather cool days up to the weekend before the weather turns briefly warmer. The forecast for the first couple of weeks of June is for the weather to be unsettled and who knows maybe we will even get some "proper" rain.

Wednesday 29 May 2019

That Was A Cold One - Almost A Frost!

The early hours of Wednesday morning produced the coldest late May temperature I've recorded in the last 10 years.

Temperature Records 27-29 May 2019

It's soon warmed up and you'd never known that we'd had such a cold early morning with the temperature falling to 3.9°C or 39.0°F. It's easily the coldest night this late into spring I've recorded as you can see from the table below. The temperatures are colour coordinated from red to blue with dark red indicating warmest through to dark blue representing the coldest nights. (Click over the chart to see a larger version)

May Low Temperature 2010-2019

At home at least the cold night doesn't appear to have done any damage. Our climbing French beans Cobra were left outside to germinate and the newly emerging leaves look unscathed this morning.

I'm hoping there are no colder nights to come. I don't expect to be providing frost protection as we move into June.

Friday 24 May 2019

Ants In The Banana

The weather over the last week has been much better, a little bit more May like, and it's meant we've made good progress at the allotment and in the garden. One of the jobs I've been meaning to do in the greenhouse was to repot our banana plant.

By the middle of summer it makes a fine plant for the greenhouse. We've tried it outside and whilst it survives okay it only takes one windy day and the leaves are shredded to pieces. In the spring the stems are cut back and new leaves soon start to form.

I always think it deserves repotting into fresh compost each spring as it grows so rampantly through summer. The plant was moved out of the greenhouse and onto the lawn to be repotted. There's a bit more space on the lawn to tip the banana plant out of the pot and to allow some of the old compost to be removed. However, as the banana plant was eased out of the pot I wasn't expecting to find hundreds if not thousands of ants.

What really surprised me was that I hadn't seen any ant activity in the greenhouse and I wasn't expecting to find anything untoward as the rootball emerged from the tub. The ants scurried in all directions into the compost trying to protect their pupae. After watching the ants for a few minutes I decided the best thing I could do was to clear as much soil off the root as possible and hopefully most of the ants. It proved a tricky job keeping the ants at bay while the soil was knocked off the root. In the end I decided to give the root a pressure wash to clear away the last of the soil and ants.

The root split into two as I was removing the soil and after pressure washing them I was left with the two roots shown above. These have been replanted into new containers to grow on.

I'm sure the main root will be okay but I'm not so sure about the root that broke away.

I'll have to keep a close look out for other ant infestations in the greenhouse. I'm already thinking that there might be a nest in the apricot tree pot. I think the tell-tale sign is the fine soil in the saucer under the pot.

Having had a quick look online I think the ants have been enjoying the honeydew produced by aphids on the peach and apricot trees but the numbers of aphids have been vastly reduced by spraying the trees so I'm wondering what else the ants may find to eat or if there is a simple way to eradicate them from the pot.

I also made a video of repotting the banana plant and the ants nest.

Sunday 19 May 2019

Running Out Of Space

Last week saw some warmer weather arrive by both day and night and the result is plants have started to grow much quicker. Suddenly it's a question of finding space for all the seedlings as they need potting on from seedling stage into larger pots.

Our home greenhouse is filling up rapidly. There's seedlings growing on for a few days before being moved to the cold frame to harden off and become accustomed to the outside world and trays of seeds still to germinate.

These are mostly trays of runner beans and climbing French beans which have only just been sown. Hopefully, they'll germinate quickly as this space will soon be required for a summer crop of tomatoes. Over the last week with the warmer weather the greenhouse has been transformed as plants suddenly decide it's time to grow. Instead of plants needing watering every couple of days due to cold, cloudy days and nights, they now have to be watered twice a day especially if the sun makes an appearance. With the arrival of warmer weather we've started moving plants to the plot. This week we managed to erect our coppiced hazel supports and get our sweet peas planted out.

The space vacated in the cold frame by the sweet peas was soon taken up by some broad bean and brassica plants. The next couple of weeks will be busy moving seedlings between greenhouse and cold frame and planting them out on the plot.

Wednesday 15 May 2019

The Cold Nights Have It!

We've had a couple of lovely days with the temperatures through the day making it into the low 20 degrees Celsius or around the 70 degree Fahrenheit mark. However, us gardeners are never satisfied with the weather. The problem is that in May, it's not so much the daytime high temperatures that cause problems but more the night time lows.

Average May Low Temperatures 2010 -2019

The table above show the running average low temperatures for May for the last 10 years. The red box highlights the average temperature by the time we've reached the fourteenth of the month and as you can see 2019 has now become the coldest with a temperature of 5.0°C or 41.0°F. Hopefully, that value will now go on increasing over the rest of May.

It's been cold enough for a light frost to catch the leaves of some of our emerging potatoes although some have remained unscathed. Checking over our strawberry flowers they all seem undamaged so not too much harm done. It's not the first time our potatoes have been caught by the frost and they've always recovered in the past.

Friday 10 May 2019

Warmth Required!

It's gone on long enough now, we need some warmer days to get things growing even in the greenhouse. Another record breaking cold day for May saw a new record low daytime high for May as the temperature struggled to 8.1°C or 46.6°F. That's only just above what we can expect as an average night time value. Gardening is on hold until better weather arrives.

Temperature & Rainfall Records 08-10 May 2018

Not only has it been cold, but we've seen next to no sunshine so greenhouse temperatures have been cold throughout the day only managing to make it into the low teens Celsius or low fifties Fahrenheit.

Greenhouse Temperature on 10 May 2019 at 10:00am

Sunshine Records May 2011 - May 2019

The table above is representative of the sunshine we've had and while it's not a measure of sunshine hours but of energy measured from the sunshine, it's a useful indicator of how much sunshine we've had. It's colour coded in my usual fashion from the highest values in red and the lowest in blue. Blue indicates cloudy days through to deep red representing the sunniest days. As you can see this May has started off with a row of blue, the first time that's happened over the last nine years.

If the forecast is correct, we should see a change in the weather next week with high pressure settling in over the country bringing with it more settled conditions and something a little bit warmer.

Thursday 9 May 2019

Cold Daytime May Day

Wednesday produced the coldest daytime high I've recorded since 2010. The thermometer struggled up to 8.6°C (47.5°F) at 13:10 taking over the record from 19 May 2012 which stood at 8.7°C or 47.7°F.

Temperature & Rainfall Records for 08-May-2019

To accompany the low temperature we had some rainfall throughout the day. It was never really very heavy and amounted to 5.6mm (0.22in) by the end of the day. We're up to 22.8mm (0.9in) of rainfall already this month, more than we had in the whole of April. The rain, at any rate, will be good for the garden and allotment although the cold weather isn't.

This May is the second coldest I've recorded at this early stage of the month. May 2012 was particularly cold early on but it did go on to warm up later in the month.

The graph above is a bit messy but it is intended to highlight extremes rather than the conglomeration of lines in the centre of the chart. As you can see the purple line representing this year's average temperature only has the red line of May 2012 below it. Hopefully, this year will warm up too.

We did have a visit to the plot on Tuesday to check if our frost protection had worked. Nothing seemed to have suffered and even the flowers on our strawberry plants hadn't been caught as they didn't have a black centre.

Strawberry - Sweetheart

However, at least one of the weather models is predicting temperatures down to freezing before this cold spell ends so we are not out of the woods just yet. We're keeping our fingers crossed though, especially for the strawberry flowers as unlike the potatoes they definitely won't recover from any frost damage.

Tuesday 7 May 2019

Stuff Stopped Growing!

It was more like the Bank Holiday weather we expect yesterday. The forecast showers held off until the middle of the afternoon but like the last few days it's been on the cold side for the start of May.

Those temperatures forecast to fall below 0°C (32°F) didn't materialise although they fell low enough for a touch of ground frost on Saturday morning (04 May 2019). However, it has certainly been a cold start to the month and in the greenhouse germination and growth rate of seedlings seems very slow. I'm putting it down to the series of cold nights and not particularly warm days even in the greenhouse.

Savoy Cabbage - Sabrosa

Newly transplanted seedlings are being covered with fleece each night to hopefully keep them a little bit warmer.

Like it or not our sweet peas and leeks have been moved to the cold frame to "harden off" although I'm not convinced it's necessary as, through the night, greenhouse temperatures will not have differed much from those outside.

At the allotment we should be sowing seeds of our carrots and parsnips but I don't think germination would be very good with such low overnight temperatures followed by cool daytime ones. I'll wait a few days for the weather to warm up, hopefully next week, before sowing seeds of a couple of our main allotment crops.

Friday 3 May 2019

Maybe May Will Be Better?

April provided us with some lovely weather over the Easter holidays but the rest of the month wasn't anything special. Despite the very warm temperatures over the holiday weekend they didn't make up for the lower than average temperatures we had for the remainder of the month. In the end April's temperatures were below its recent averages. April did manage one record for my weather station though, when 13 April produced the lowest April temperature in 10 years falling to -2.6°C or 27.3°F.

April Temperature & Rainfall 2010 - 2019

April produced another month of below average rainfall. It seems that April has often turned out to be a dry month over the last few years. It's meant we've had to start watering on the allotment already.

Over the coming weekend the wind is forecast to turn into a northerly direction bringing with it some unusually cold temperatures for the beginning of May. Saturday and Sunday mornings are forecast to be particularly cold with the possibility of a frost each morning. We couldn't decide whether or not to try and protect our potatoes on the allotment. They are just beginning to send up their shoots which are easily damaged by frost. This has happened to our potatoes in previous years and while the potatoes always recover from the damage I've no idea if it has any effect on the eventual crop. It must at the very least delay the crop.

Potatoes Casablanca & Athlete

Our early potatoes, Casablanca and Athlete, were the easiest to deal with as they aren't planted through weed control fabric and some soil was earthed up around the freshly emerging haulms. Our potatoes growing through weed control fabric posed a different problem as it's not possibly to cover them with soil.

Trial Potato Bed

Fortunately, we had some old straw left over that had been used for winter carrot protection. It was all used up protecting as many of our remaining rows of potatoes as possible.

For good measure we covered our newly planted kiwi, Issai, with some enviromesh. Its new shoots were badly damaged by the earlier frosts in April.

Kiwi - Issai

It is just starting to form some new shoots and we didn't think it would like these tender new shoots freezing and might give up the will to survive altogether and so it got an environmesh duvet to protect it.

Unfortunately, it looks like that forecast of the winds turning into a northerly direction are starting to occur through Friday morning.

Above is the latest output from my weather station indicating the wind has moved into a north easterly direction. The temperature is getting cooler as we progress through the day with a low temperature so far of 5.5°C (41.9°F) at 09:20 compared with a high of 7.8°C (46.0°F) just after midnight. At 11:00 the temperature is 5.6°C (42.1°F) well below what we expect at the start of May.