String of Turtles Complete Care Guide - What no-one tells you (and how not to kill them)

Say hello to Peperomia Prostrata, aka String of Turtles. Count me in. I'm officially and totally obsessed with these little cuties. But how do you go from a cute teeny-weeny cutting, to lush overflowing, trailing, insta-worthy plant? 

The good news first. They ARE easy care. Once you know what to do (and what NOT to do). Especially once they are established (or if you start with a more mature, bigger plant). In fact, this is not the plant you want to be a helicopter-plant-parent over. However, there are a few big NO NO's to be aware of also...

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String of Turtles quick reference 

(the 'too long didn't read' version)

SOIL: Free draining, fine, soil-less substrate.

HUMIDITY: Very high preferred.

WATER: Lightly moist (never wet).

LIGHT: Bright indirect light (no direct sun unless weak and used to it).

HEAT: Warm. 

FOOD: Little and often (with calcium!).

= happy turtles! 

String of Turtles Ultimate Care Guide + Trouble-shooting...
 

What potting mix do String of Turtles prefer?
 

Like other Peperomia, a free draining mix is key for String of Turtles success to avoid the dreaded leaf and stem rot. I prefer a soil-free mix as I find soil-based and peat-based mixes hold too much water, increasing the risk of root rot. However a mix that does have soil or peat in it can still work provided you balance it with airy, free-draining ingredients (and of course, don't over-water!). Because of their shallow, fine roots, I've had the best results from a finer-grade mix instead of something too chunky. Your pot choice matters too with these guys. Too big and the extra soil in the pot will hold too much water, not drying out fast enough, so stay on the small side. I also fine shallow pots much better than standard or deep pots because of their shallow roots. 


What I use: I've tried different mixes for my Turtles. My favourite is the Bioleaf Soil-Free Fine Indoor Blend as because its a complete mix, you don't have to fuss with adding anything else.

String of Turtles potting mix recipe: If you want to DIY your own mix without getting too complicated, option 1 is to combine 2 parts succulent or cactus mix with 1 part plant plant pumice. Or if you want to go full DIY for your turtles, option 2 is to mix 1 part fine-grade orchid bark, 1 part peat moss, 1/2 part fern fibre and 1/2 part plant pumice.

For my overseas readers with Amazon as an option: For option 1 go for 2 parts Espoma Cactus Mix and 1 part Tinyroots Horticultural Pumice or for option 2, 1 part Miracle Gro Peat Moss, 1 part JK Orchid Bark, 1/2 part Fernwood Fern Fibre and 1/2 part Tinyroots Pumice.  

What's the best substrate for propagating String of Turtles?

I've tried all sorts of substrates for propagating String of Turtles and the most successful for me has been spagmoss. Turtles cuttings root super easily in it, but spagmoss can be fiddly to take off roots later without damaging them. I soak off what I can and just leave the rest on when I pot them up. Simply resting the leaves stem down on spag moss (kept lightly moist, never wet), works a treat.

Another good option is a fine-grade succulent mix, or starter mix (half perlite, half vermiculite). However for those substrates I find best results from starting with a stem with multiple leaves on it, then gently removing the bottom 2 to 3 leaves and pushing the bar stem end into the substrate.

Whatever you choose, beware of keeping it too wet or leaves can rot before they root. With spagmoss I find you don't need to pin the leaves down or push the stem into the moss to keep the stem in touch with the substrate as it's naturally fluffy and fibrous so the leaves can just rest on top. With succulent mix or starter mix it does work better if you pin the stem down in touch with the substrate surface (I find soil pins perfect for that).

I've had turtles root successfully even from single-leaves with a little stem attached, but find you'll have more luck if you can get a short section of stem with a good 4 or more leaves attached.

I use Besgrow Spagmoss myself (that's the link for those in NZ), or you can get Besgrow Spagmoss on Amazon too if you're in the US. Since humidity is key for these little cuties, I combine spag moss with these mini humidity-dome propagation kits. Warmth helps too (aim for 18 to 25 degrees). If you're not local, you can get similar humidity-dome propagation kits on Amazon also.

What light requirements do String of Turtles prefer?

Turtles do best in medium to bright indirect light, and definitely no direct sun on babies and smaller turtles. They have a clear almost jelly-like layer on the leaf which sun can quickly cook. Best avoided! Once established however, my String of Turtles are more sun-tolerant but I'd still play it safe and go for weaker sun, like weaker morning summer sun, or morning or afternoon winter sun, rather than harsh midday or any summer sun.

What temperature and humidity range do String of Turtles need?

TEMPERATURE

String of Turtles like the same temperature range we are comfy in. The more mature the plant the more temperature tolerant it is and turtles that you've grown in your conditions from a cutting I also find more temperature tolerant. Aim for about 18 to 29 degrees Celsius (64 to 84 Fahrenheit). A little cooler than some other succulents (Turtles are actually semi-succulent), so watch those hot temperatures in summer to avoid scorching and heat stress. Once you get up to the mid 20's (or high 70's in Fahrenheit), good airflow and no direct sun becomes more important to avoid scorching. Too cold however can result in leaf drop for String of Turtles, so keep an eye on those highs and lows.

Get yourself a cheapie digital plant thermometer to help keep an eye on conditions (those ones monitor humidity as well which is a biggie for happy turtles), or if you're not based in New Zealand, have a look at the ThermoPro Indoor Meter available on Amazon which also monitors both temperature and humidity. 

HUMIDITY

Coming from the Brazilian rainforests, String of Turtles love both warmth and high humidity, but once settled in to your conditions are more tolerant of drier air. Aim for above 40% but for super happy turtles, keep humidity from 70% to high 80's. One reason String of Turtles thrive in a humid forest or rainforest terrariums. 

A warning about winter though. Most artificial heat sources will strip moisture from the air. Using one of those mini cordless humidifiers is a superb fix for winter or when humidity drops below 40%. In winter I just pop my turtles in my converted Ikea cabinet which naturally keeps humidity higher as it's enclosed. Either way, I would definitely get a humidity meter (two good options linked under Temperature for you, above).  

Getting watering right for String of Turtles

Being a semi-succulent, it's better to err on the side of caution and under-water rather than over-water your String of Turtles. Keeping humidity high makes it much easier to get watering right also. A humidifier does a great job getting humidity up, or just keeping them in a terrarium, but I've personally found misting my turtles a waste of time. It only lifts humidity for a short time and wet leaves have a higher risk of rot. If you prefer to mist, then mist in the morning and keep airflow up so leaves dry before the evening.


Beware over-watering your String of Turtles. They hate wet feet so a pot with drainage I find is a must. Overwatering can quickly turn your string of turtles into a mushy turtle soup if you're not careful. Over-watering has nothing to do with how much water you give them, but how often you water. When you do water, because of their shallow root system and fine roots, you want to water until all the substrate is saturated. Watering too lightly can leave the roots dry, which can kill the root hairs and lead to root rot next time you water.  

Bottom watering is popular for String of Turtles to avoid the leaves getting wet. I top water my turtles once they get some size on them because the roots are so shallow and I water in the morning so any wet leaves dry by evening. If you prefer to bottom water, a potting mix with soil or peat moss in it helps draw water up to the roots, and planting in a shallow pot is better for bottom-watering so the roots don't miss out. When bottom-watering, soak long enough until the top surface of the substrate is moist and remember to drain well either way. 

Why do my String of Turtles lose leaves?

Cold temperatures is a common reason for String of Turtles to drop their leaves but sometimes leaf drop is just our fault for moving them! These guys are not huggers. Definitely not fans of being touched too much. More delicate than their turtle-shell leaves appear. I find their leaves fall off annoyingly easily. Although my new obsession is silica (which strengthens roots, stems and leaves), and I can report GT Silica is making a great difference to reduce leaf drop for my turtles. More about fertiliser coming up, but like the rest of the peperomia family, a fertiliser with calcium in it does wonders for turtles too.

The moral of the story? Find your String of Turtle's happy place, then largely leave them be. Especially once those leaves start trailing over the edge I'd avoid moving them unless necessary. I am a bit of a meanie with my turtles and regularly grab the snips and prune off all the ends at least once during each growing season. I find at least 2 or more stems grow back which creates a much bushier plant long-term.

Why are my String of Turtle's leaves so small? 

It's normal for your String of Turtles new leaves to start off really small and beautifully marked, then grow larger over time and lose some of their markings as they do. Another reason for tiny leaves that don't size up is a lack of calcium. A calcium deficiency can also cause leaves to split, crack or curl. 

What are my String of Turtles leaves fading?

Despite their semi-succulent nature, these are rainforest succulents, not desert dwellers. Found protected from direct sun under the rainforest canopy. The most common cause of fading is simply too much light. You'll also find too much light causes them to lose their variegated turtle-shell markings faster. The markings on mature leaves do tend to fade slightly as they age, however shifting your turtles to a more medium-light spot should help them keep those gorgeous markings.

What's the best fertiliser for String of Turtles?

Despite being relatively slow growers (especially at first), that just means turtles need less fertiliser, not no food at all. The Weekly Weakly Method works a treat for String of Turtles (which just means little and often, every time you water, not literally once a week).

The first thing I've found for choosing a good String of Turtles fertiliser is one that includes calcium. Most fertilisers don't. Like other Peperomia, String of Turtles  (Peperomia prostrata), benefit from calcium for bigger, stronger leaves (calcium is an essential nutrient for them). My go-to fertiliser with calcium is GT Foliage Focus but another option is Superthrive Foliage Pro (those links are where to get them in NZ, so for those overseas you can also get GT Foliage Focus on Amazon and Superthrive on Amazon here). Either way, I use fertiliser at half-strength for my turtles, every time I water. 

Another benefit of GT is for slower growers and variegated plants. Being naturally slower growers, the risk of fertiliser burn is higher with String of Turtles. Growing slower means the mineral salts in fertiliser get used up more slowly also, increasing the risk of excess salts building up in the soil and burning roots. GT is a reduced-salt fertiliser, still giving plants everything they need, but without any sodium, chlorides or urea (Superthrive Foliage Pro is urea-free also). For baby turtles and propagating cuttings, GT also makes a gentle reduced-salt root fertiliser that includes calcium, called CCS. 

Also keep in mind when feeding turtles that free-draining substrates, higher in ingredients like bark and pumice, means they are naturally lower in nutrients, so providing those nutrients with regular but light fertilising becomes more important. I haven't found turtles to be heavy feeders, but in a very free-draining, soil-free mix I'd fertilise lightly every time you water.

If you're new to turtles or having any worries, I hope this guide helped. My first String of Turtles cost about $150 NZD (that's about $90 USD), which I almost killed! I'm so pleased the price has come down and they're more readily available.