When plant people refer to spent nodes, they’re talking about nodes that are no longer able to produce new growth.
I’ve seen some people confuse spent nodes and zombie leaves, but they’re actually kind of opposites.
A spent node is a node that won’t grow, a zombie leaf is a leaf that has rooted but has no node, so it can’t produce any more leaves.
A common example of zombie leaves is Hoya Kerrii, which are often sold as rooted single leaf cuttings. On occasion, they can produce more leaves, because there’s a node beneath the soil, but it’s the exception rather than the rule.
The issue here isn’t a spent node – it’s that there probably isn’t a node. It’s just a rooted leaf that will eventually die.
I often see people talking about spent nodes on social media, usually when responding to people who are sad that the wet stick they bought hasn’t grown. Often, it’s blamed on spent nodes.
There is a LOT of controversy on this subject, but the general consensus is that spent nodes aren’t really a thing.
What is a spent node?
A spent node is a node that doesn’t grow.
Loads of people who’ve bought wet sticks to propagate attribute their lack of success to the fact that the node they bought was ‘spent’, meaning it won’t grow.
A node is also considered spent if the cutting is producing roots but not leaves.
At the moment, there is no evidence (that I can find, anyway) that a plant that is only growing roots will never grow leaves. You’ll just have to be patient.
Plants grow at the discretion of hormones called auxins, which are responsible for promoting the growth of roots AND leaves.
The plant wants to live. If it can grow roots, it has the potential to grow leaves.
Either there’s something physical stopping it (which can occur in very thick cuttings, but they’ll break through eventually) or the conditions in the surrounding environment aren’t conducive to plant growth.
In other words, give the cutting the right conditions (and be patient) and it will grow.
By the way, there are a LOT of unscrupulous sellers selling wet sticks on Etsy and eBay that are selling dead sticks, or random sticks that they found. Read the reviews, and if it seems too good to be true, it probably is.
Buying plants online is already a game of dodge-the-scam, buying wet sticks and seeds is even worse.
Can a spent node grow?
Yes. As we’ve already established, there’s no such thing as a spent node.
If you’ve been waiting an age for your plant to produce a new leaf, or you’ve bought a wet stick, there are three aspects of the cutting’s environment that you need to control:
- Light
- Humidity
- Temperature
Light and temperature are fairly straightforward. Bright light (such as from a grow light) can stimulate growth BUT the new leaf may come out damaged, or shrivel up halfway through emerging.
I put mine under a grow light that’s dimmed down a little, but any spot in your house where plants thrive will work.
In terms of temperature, you want your plant to be warm, but not hot. In my experience, 22oC (about 70oF) is about right.
Humidity is MASSIVELY the key to activating nodes. Light and temperature can only go so far, especially when we’re talking about plants that come from tropical rainforests.
I’ve found it’s easier to buy large, established plants and grow them well than buying baby ones and growing them up – especially if you don’t want to invest in a grow light and/or humidifier.
Once a plant has produced a few big leaves it’s likely to continue to do so, provided the light and humidity are ok.
But if you buy a baby plant, you have to give it more resources than it technically needs to survive to produce bigger growth.
You need to convince the plant that it’s worth using all its energy.
With wet sticks that are only growing roots, you need to convince it that it’s worth producing a new leaf. If you want an in-depth guide to propagating cuttings faster, read this article.
Roots will keep the plant alive until better times (i.e. the growing season), so if conditions aren’t great, the plant will decide that it’s better to put all that energy into its roots, and then when summer comes, it’ll have a big root system and be able to produce stellar leaves.
To the plant, that’s a better option than growing a crappy leaf and having a crappy root system.
If your wet stick isn’t growing and you’re sure it’s still alive, I’d try putting it in a clear plastic box with some damp sphagnum as substrate, and putting it in a warm, bright spot – a bright windowsill is perfect, but I swear by grow lights.
What’s the difference between a node and an axillary bud?
Axillary buds are basically buds that have the potential to turn into leaves.
Some plants, like Monstera, have barely detectable axillary buds that just look like a paler green spot on the stem:
The specimens that are really flourishing (i.e. not like my thrips-covered one) have more obvious axillary buds.
Here’s one on a Syngonium tri-leaf wonder:
If something happens to the growth beyond that bud, that bud will be activated (by the auxins) and it’ll start to grow.
A node is a whole area that produces the axillary bud, the leaf, and the aerial root.
How do you encourage growth from a node?
Different plants have different growth patterns. Monstera rarely produce two leaves from the same node, so the axillary bud won’t do anything unless the top growth is compromised.
1- Random chance
Rhapidophora tetrasperma just randomly decides to one day activate an axillary bud and start another growth point. Mine did that for no clear reason:
It’s now growing out of the node closest to the soil AND the one at the end of it’s (very long) vine. To encourage a bit of bushiness I’ve stuck the newer nodes in the soil, and I’ll cut them off the mother once they’ve rooted.
3 – High humidity
You may have seen in my other articles that the RT in my terrarium has activated the axillary bud on every node, so it’s got a tonne of growth points. I was pretty sure it was due to the humidity, and that was confirmed when I recently bought a Philodendron brasil.
The P. brasil had clearly been kept in a very high humidity environment (I could tell because of the fuzzy aerial roots), and quite a few of the axillary buds were, er, no longer axillary, and were new growth points:
It’s even growing two leaves out of the same node simultaneously:
Unfortunately, I can’t keep up the super high humidity (it was probably kept at about 85% humidity in the greenhouse), especially on a big plant, but if you have a large terrarium, it can be a great way to encourage growth from nodes.
4 – light
My Syngonium had a bad case of thrips, and I had to cut it right back (and switch it to leca). Only a couple of the vines were growing BUT when I moved it to near a grow light (next to it, not even directly under it) it activated another couple of nodes:
Haha I was just casually wondering why the plant decided to activate the second node from the end, but it’s actually got one on the end node too:
The lower one is the one in the picture above this one, but there’s another one too!
Light = energy for plants, so if you can give better light, you can potentially activate multiple nodes.
5 – notch the plant
This isn’t something I’ve done, but I’m gonna try it on my rubber tree because…I want to see if I can do it.
This is the video I watched to learn how to do it. I’ll post updates when/if it works!
You basically scrape off the wood of the trunk, make a notch, snip off the growth point so the plant can concentrate on making a new one, and wait.
TL;DR
- spent nodes aren’t really a thing you need to worry about
- give your plant plenty of light, humidity, and warmth to activate nodes
