Bulbs spring fertilizing

[blagoves]

Hello Ian,

While at your weekly bulbs log, a few times I came across the potash feeding in the middle of growing season of the bulbous plants. What is your take on feeding with Nitrogen just after the new growth begins to give a boost to vegetation stage? Or the bone meal applied in fall should suffice?
Most of my bulbs have already poked their heads through the ground.
There are so many organic products out there and it is really tempting to apply something like blood meal, cottonseed meal etc.
Thanks for the input,
Anastasia

[Ian Y]

Hello Anastasia, sorry for the delay in replying but I am still trying to catch up after my month away.
I do not add any extra nitrogen as there is sufficient in the bone meal. If you think your bulbs are struggling to put on leaf growth and look like they are suffering from a lack of nitrogen then you could apply a light dose.
In my experience bulbs do not need heavy doses of nitrogen and if they get them they become very leafy and soft and this increases their vulnerability to fungal and bacterial attack.
Potassium is what they need plenty of to store away for next year.

[Luc Gilgemyn]

Ever tried potassium on Pleione Ian

[Ian Y]

Luc, we haven't fed potassium to Pleiones.... they're not  "real" bulbs, after all!
When we did try feeding Pleiones, in the distant past, we used Osmocot fertiliser and got HUGE pseudobulbs and no flowers ....went back to leaving them be.... until the pleoine bug wiped them out a couple of years ago... they did well untill then, though. We only gave thenm a little liquid feed in those years...... can only suppose that, as a storage organ,  a little potassium to give them some starch to grow on  might be helpful.... someone will either have to try it out or tell us what happened if they already did try it!!

[blagoves]

Thank you very much, Ian. This is what I thought.

BTW, I am very jealous of your recent trip and the pics look gorgeous too!

[Luc Gilgemyn]

Thanks for filling me in Ian - I normally only feed them tomato fertilizer myself but I may do a careful test and see what happens.
Where your Pleione whiped out by Brevipalpus Ian ?

[Maggi Young]

Where your Pleione wiped out by Brevipalpus Ian ?

YES! 

[Lesley Cox]

Luc, I do pot my Pleiones with Osmacote in their compost, but I use the high potassium formulation, with trace elements, 9 months. They're not fed otherwise. The pseudobulbs grow to a good size, though not "huge" as Ian suggests and I get a great many flowers.

[johnw]

Ian - I really enjoy your bulb blog, thanks.

I am trying to find out which potassium sulphate to use as you suggest.  There are many types available here. The one that most resembles yours physically (the grade of table salt or slightly finer) is 100% water soluble and the analysis is 0-0-50. Now that means it has little residual effect, is one application per year sufficient if this is the one? Is this the one?  Another has coarse granules that is slow release, same analysis. As well of course there is muriate of potash which I avoid. Are any of these the same as the one you use? The cost is about 18GP/25kg & the price is due to go up by 50% shortly.

Would this be safe to use at this time of year on all bulbs including cyclamen and some southern hemisphere bulbs (I avoid potassium on the latter as a rule. Am I correc or is it just New Zealanders?).

I have quite a collection Nerine hybrids from the Smithers. From what I read and from his notes all fertilizer is to be avoided. In fact I struggled to come up with a nutrient poor mix - peat-sand 50/50, that's it. In the last 10+ years I may have given them a half dozen applications of 1/8 to 1/16 strength water soluble fertilizer. They bloom well but this year the leaves are smaller than usual. Am I being too cautious? 


thanks


johnw

[Lesley Cox]

John there are no New Zealand bulbs at all so your non-fertilizing regime doesn't apply to those.  I'm interested that you don't fertilize nerines though as some of mine are not flowering well - they're not yet in need of clump division - and I was about to give them some sulphate of potash. I bought some a few days ago and it seems to be a powder, not sugary or salt-like. It is 0-0-42-18, N-P-K-S.

[johnw]

Leslie - I didn't realize there were no NZ bulbs! I was referring to things like Proteas and Puyas and other southern hemisphere  plants which we were told hate potash & potassium.  Have you found this to be the case?

My Nerines have been repotted about 3 or 4 times. All seedlings of each hand-pollinated cross from Smithers are in one pot. All are now in 6" deep pots and the pots are bulging and ready to explode. I have far too many pots and can hardly afford the space even larger pots would require. There are some wonderful colours ranging from smokey purples to whites, clear reds, salmon oranges, oranges, pinks...the whole gamut, much as you see in his book "Adventures of A Gardener". They are a real joy at a barren time - October until the new year. I put a label around the neck of each bulb and record the colour each year along with a flower per stem count. It is quite amazing to see the different colours a single bulb will exhibit over the years making it very difficult to discard what ones thinks of as a dog.

The one time I did fertilize them a bit more than of late I got some basal plate damage though they recovered.  Peter Smithers says in his book "Soil need not be rich and all fertiliser is dangerous, encouraging basal rot and virus." It will be interesting to hear what others have to say about mixes and fertilizing.

johnw

[Ian Y]

John
I have no experience regarding the South African bulbs except for the Nerines we have in the garden - they do get sulphate of potash on occasions.

The soluble potash you mention sounds fine, the one I use is not fully soluble that is why I sprinkle it on the surface. I do apply a second dose in the years when the bulbs grow on for a long time. Last year for instance we had a very hot spell in April which caused most of the bulbs to start to go dormant so they only received one extra feed. In other cooler years I have to withhold water in June to force them to go dormant so that I can repot them - then they got two feeds.

I would think that as your potash is 100% soluble a dilute liquid feed could only be a benefit to your potted nerines and other South African Bulbs. We are always reading about how much better they flower after a big fire -the fire releases potassium as well as removing the competition leading to the mass flowering.
Caution is required with chemical fertilisers as too heavy a hand could led to burning of the roots but I have never had any problems with mature bulbs. I did experiment with newly germinated seedlings and they can be damaged it is best to wait until they are at least two months old before applying a diluted dose.

[mark smyth]

I feed my Nerine sarniensis at this time of year with SoP dissolved in water. I have also moved them outside now

[johnw]

Ian & Mark - Thanks so much!

johnw

[Lesley Cox]

I was referring to things like Proteas and Puyas and other southern hemisphere  plants which we were told hate potash & potassium.  Have you found this to be the case?

John I don't grow proteas, leucodendrons and the like but I do grow some Australian trees and shrubs, acacias, eucalypts etc and those are also supposed not to like chemical fertilizers of any kind. Certainly mine don't get any but that's more a matter of laziness/lack of time than a positive decision to refrain. I grow some small nerine species such as filifolia and about 30 different hybrids of small stature which appeal to me more than the larger kinds. These too, I've not fertilized though I was planning to give them a little potash this year. Now I'm not so sure, following Mr Smithers' advice. Not every one flowers each year. I'll post a few pictures when they are in flower, the buds just coming through now. In general, they are exactly like the larger hybrids with a great colour range, but everything smaller in proportion. As an example, one is the same scarlet orange with that lovely glistening quality, as N. sarniensis but the stem is less than 30cms high, and very fine (though sturdy) while the flower head is about 6cms across. My N. sarniensis are just about finished now.