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Renfrewshire, Scotland Sco

What is happening to my lupin seedlings?

I have tried growing some lupins from seeds. The variety is Band of Nobles. I sowed the first batch in a seed tray in September and they germinates quickly. They spent some time outside with a transparent cover and seemed to be doing well but only ever produced a pair of true leaves. They then all died off gradually.

Then in October I sprinkled 4 seeds into a 4" pot and they also germinated quickly. They have been kept indoors and under a polythene cover. They go on a windowsill when during the day and off it at night. Again, they seem to be dying off having initially appeared healthy.

Anyone any idea what is happening. According to the seed packet, I should be able to grow these in a room indoors between 15-20C. So, I am puzzled.

I thought that the original batch may actually have been too warm as we had a bright, sunny spell when they germinated. However, their cover was being taken off during this spell and the seedlings brought indoors at night.

I think now I will need to wait until March and try once more, but am curious as to what has gone wrong here?

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It's hard for me to ascertain without a photo so now I can only go by what you say. I don't know what is going on with your lupins but they are bi-annual plants - maybe a strong one with give you three years. These grow natively up in Canada so they like cold weather. They usually bloom the 2nd year.

14 Nov, 2020


I have posted a blog for you on root systems of lupins, which were sewn in early May, hope this helps.

14 Nov, 2020


Thanks for the responses and the blog.

The roots on the failed seedlings were very poorly developed. I am not sure if this would be normal for young seedlings. Maybe a single, short thread like root - 2/3 at most. When I examined them, I was not surprised that they had failed to develop as the top growth was significantly better than the root development.

As I am in Scotland and have grown lupins many times from pot plants, I know that they are happy in this climate. At least they are outdoors. So, I am puzzled as to why they keep failing.

14 Nov, 2020


Interesting. I have grown some Lupin seed this year from a neighbours garden and had good germination, like you did and like yours they have gradually failed. Oddest thing is that in a previous garden I never had to collect the seeds as there was always a good number of good sized seedlings round the parent plant which I could dig up.
Wondered if it was some problem with the compost, but other things have grown well in it.
Also for supposedly biennial plants, the ones in our neighbours garden were given to them when they moved in 10 years ago.
The ones in our previous garden survived for many years only succumbing in the end to Lupin aphids.

14 Nov, 2020


Thanks, Owdboggy. Interesting that you had the same issue.

I have grown lupins from plants many times and they have lasted longer than 2 years. In fact, some seemed to succumb to a severe winter a few years years back otherwise, I have a feeling that they would have continued. Several other plants were lost that year.

I have also a lovely yellow one just now that is at least 5 years old.

I actually thought of them as perennials until recently.

14 Nov, 2020


Band of nobles are a good perennial lupin, I have some that are 10 yrs old. is there anything left in the compost? I'd expect late ones to die back now anyway as they don't keep leaves all winter. The growing part or 'crown' could well be below soil level and will grow away again in the spring. I usually start mine off in Feb/March. put the pots outside with some shelter but not in a rain shadow and you may find you get new ones next year.

but they usually have a very strong root almost like a tap root in my experience.

There are many types of lupins from annual to perennial as well as shrubby/woody ones.

If it were me I'd set more seed off in the spring.

15 Nov, 2020


There are 2 seedlings left in the compost. Neither doing well, but I will keep going with them until they die too.

I have decided to do what you are suggesting. It is too late to start any now this year so it will need to wait until spring, but I am worried that the same cycle will simply be the case then also.

15 Nov, 2020


I've always direct sow my lupins - it never fails. They have a large tap root so transplanting them could be dicey. Also don't keep them too wet - just slightly damp and they need lots of sun and good air. Also don't fertilize your lupins. It will burn the roots. Here is this...

'Easy to grow, lupine thrives in cool, moist locations. It prefers full sun to light shade and average soils, but will tolerate sandy, dry soil. Plants develop long taproots, so loosen the soil to a depth of 12-20 inches using a rototiller or garden fork. They will not grow in clay.
Sunlight: Full sun to light shade
Maturity: Days to bloom varies depending on fall ...
Spacing: 12 inches'

15 Nov, 2020


Thanks Bathgate. I do wonder about the moisture in the soil. Although the compost is not too wet and I have mixed a lot of sand and grit in this batch, seedlings do seem to perish after watering. I only water when the surface of the compost appears to be drying, but still wonder if the roots are too weak to cope with this.

16 Nov, 2020


is the sand builders sand? If you do use builders sand it might be worth washing it first to remove any salt that might be present.
I always start mine off in pots 9cm wide and tend to use a soil based compost [John Innes No 1] when they get 4 true leaves and if the root is down to the bottom of the pot I then transplant them into a bigger pot.

When do you move your seedlings on to the next pot? I wonder if you are doing it too soon. Also they wont need covering, that will encourage damping off which is a fungal infection.

try watering from the bottom. put the pots on a tray and add water to the tray.

16 Nov, 2020


To be honest, I cannot remember where the sand came from. I have had t in my garage for many years. It is very likely though that it would be builders' sand as I certainly have not bought sand from a garden centre.

This set of seedlings have not been moved on to another pot. They are still in a 4/5" pot where they were sown. The first set were sown in a tray and moved into a separate cell tray when they started to show their first pair of true leaves. The roots on these were very fine and sparse.

16 Nov, 2020


Forgot to mention. The first set of seeds sown in the tray were sown into ordinary seed compost - Miracle-Gro I think - without adding any sand or grit. I am not a fan of the new type of compost as it appears to me that it contains a lot of composted paper type material. This is why I added sand and grit.

16 Nov, 2020


Added some pics and from these you can see the corpse of the dead seedling. It also looks like the other larger seedling is going the same way too.

16 Nov, 2020


they look to be 'damping off' that is a fungal disease. Too moist & warm. Avoid composts with added 'feed' such as miracle grow. good air circulation and cooler conditions. Band of nobles strain will grow in an unheated greenhouse from about Feb/March.

I think it is a case of killing with kindness.

16 Nov, 2020


Thanks, Seaburngirl. I'll try that next February and hopefully have better luck.

16 Nov, 2020

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