Known collectively as cucurbits (Latin name: Cucurbitae), the squash family includes cucumbers, pumpkins, melons, and summer and winter squashes. Squashes in particular include a range of weird and exotic shapes and sizes such as Patty Pan, Spaghetti and Hokkaido varieties.
Common to many of these plants are their gorgeous, edible yellow or orange-coloured flowers. Many inexperienced gardeners think this might be a good plant to grow vertically on a balcony or to save space, but is this the best way to grow squash?
This article will explain the best conditions for growing squash and uncover how to support your fruit as it grows in size.
What do you need to consider when growing squash?
Light These plants are not going to be content in a shady, dull area of your garden. They need sun and lots of it. Squash is commonly grown in Mexico so give these plants the sunniest position you can find so that you can enjoy delicious crops from August onwards.
Soil Quality The soil needs to be full of nutrients. Squash loves well-rotted manure, plenty of humus and ongoing feeding. Make sure you dig in some manure at least a month before settling in your new plants but preferably prepare the bed early in spring and then leave the ground to settle. In the meantime, you can add some comfrey leaves to decompose which will provide long-term nutrition.
Support If you plan to grow squash vertically, rather than letting it sprawl over the ground, be aware that squash fruits are heavy and will need sturdy support. Growing beans up bamboo canes is fine because beans are light, imagine the weight of a plump butternut squash and you begin to understand the issue of vertical growing. You can read more about supporting your squash plant below.
Water and Fertiliser This is really important. Your developing squash may wilt on the stem if you forget to water it. They need regular watering from seedlings to mature fruiting plants. As soon as the squash plant starts to develop fruit, it’ll also need a feed at least every 2 weeks. You can use tomato feed, make comfrey feed or use both. You can also set up an automatic watering system so you do not forget.
Harvesting This is the joyful part! One trick I have learned is that if you do not pick the first squash then the whole plant may go to seed and no more flowers or fruit will develop. So even if that first squash is not to your desired size, remember this is the first of many. Use a pair of sharp scissors or secateurs and cut it at the stem. Remember that the flowers are usually edible too, but these become the fruit so leave some to develop into squash or pumpkins. After you pick the first squash, leave the rest of the flowers to develop to full size, feeding weekly if possible.
Storage Some varieties of squash are not meant to be stored, including summer squashes. There are some excellent varieties of storing (or winter) squashes, however. One of my personal favourites is the Japanese Hokkaido squash. I very luckily bought some organic seeds years ago and each year, I save seeds for the following year. Check your seed packet carefully when you buy and then choose varieties depending on when you want to eat them. See more about storage below.
Will squash grow well vertically?
Definitely! Your squash plant will use its tendrils to attach itself to anything in the vicinity! It can be tied in and supported on bamboo, trellis, and exotic DIY structures so that you can easily grow squash on your balcony, garden or allotment.
How to grow squash vertically on a trellis
There are a few important conditions when it comes to growing squash vertically. Read on to find out how to grow squash vertically for the best results:
1. Pick a strong natural trellis
The support needs to be able to support the weight of 5-8 squashes per plant. Think of holding 5 butternut squash in your arms and you realise how much weight may need to be supported. Of course, you will pick some squash as they grow but by September you may have 4 or 5 squash fruit ripening in the early autumn sun. Make sure the support is dug in well and stamp the ground to ensure it is steady.
What’s the best trellis for growing squash? Squash plants prefer to wrap their tendrils around natural materials rather than plastic or polythene. This is not scientific – just my personal observation. If I offer a metal pole, a plastic trellis, a wooden trellis, a bamboo cane or a pruned branch the tendrils inevitably aim for the wood or the bamboo. You can help tendrils by tying them around the support and fixing the leaves so they are supported.
2. Tie some strings between posts
The width of the support onto which the tendrils climb needs to be thin enough for them to attach to. A way to help with this is to use sturdy stakes or canes or trellis with some string tied between posts so that tendrils can attach to the string and then leaves or fruit can happily rest on this. When I prepare my support, I always leave a few pieces of string hanging, ready to tie in any new growth.
3. Don’t water the leaves
Remember to water the roots, not the leaves. The same applies to fertiliser. The leaves often complain if hosed by getting mildew and turning grey. Avoid this completely by aiming at the roots, not the leaves. If you notice grey leaves, chop them off and dispose of them so as not to spread any fungal disease.
4. Make a mini-nest for each fruit
Support each fruit separately. Use the netting around orange fruit, or get creative with any materials to hand. Some allotmenteers use tights, old bras and scarves or you can make a mini-nest with string and rest the developing fruit on here.
5. Space out the plants well
You can plant a well-spaced row of squash, giving them each individual support and I recommend no more than 3 per household as they are prolific fruiters. If you are growing different varieties; summer, winter, courgette, pumpkin etc, why not try growing some on the ground and some vertically and compare the results? Give them about 2 feet/60 cm between plants to allow for the spread horizontally and vertically.
I have spotted squash growing from a busy road in my neighbourhood in Kent, where the seed landed on waste ground and then grew up past tall grass to reach the sunny railing above.
How do I know when squash is ripe?
- Size is a good indication. Check the expected width and length size on the seed packet but always cut the first fruit that arrives, even if it is not quite the desired size. This forces the plant into thinking it had better produce more if one is already gone, so the next fruit will tend to be larger and you can leave them to swell.
- Colour. Once they start to turn from green to yellow or orange, this is an indication that your butternut squash or pumpkin is nearly ready. Other cucurbits like courgettes will remain green but their skin usually changes from light green to a more intense colour and a pattern becomes more evident too. Water the plant frequently at the roots and allow the fruit to turn a golden yellow, orange or intense green.
- Check the top of the fruit close to the stem. This normally turns to brown or a sandy colour as it ripens. Then cut with a pair of sharp secateurs and move them to dry slowly, in a frost-free shed for winter curing.
Can you store squash for the winter?
Summer squash is best eaten fresh so eat it when you pick it. This group includes annuals like cucumbers, courgettes, and patty pans – the zigzag-edged squash with soft flesh. Their skin is usually thin and easy to cut.
Winter squash can usually be stored until December or January. Their skin is thick and it cures to a hard surface, which is quite difficult to cut. These include butternut squash, spaghetti squash, pumpkins, Crown Prince squash, Hokkaido squash and Sweet Dumpling squash. If your squash can be stored, cut them before the first frosts and then store them in a dark shed on paper or straw, and use as required. Check them regularly and if they seem to be deteriorating, bake them immediately. They never last long in my house!
These squash were cut on my allotment late in autumn in misty fog, just before the arrival of winter frosts.
What are the best varieties of squash for the UK climate?
If you live in the south:
- Butternut squash
- Outdoor cucumber
- Exotic squash
Anywhere further north than the Midlands:
- Outdoor cucumber like a lot of rain so if your area gets plenty, it’s a good one to try!
- Hokkaido squash comes from a Japanese island known for lots of rainfall and it stores really well for winter too.
- Hardy winter storing butternut squash varieties can be grown indoors in May, then planted out after all risk of frost has passed. Pick fruit early and you can bring them indoors before the first autumnal frosts to harden them up. Further north, these have a shorter growing season than more southerly regions so you will probably harvest less fruit. Maybe try growing these in sheltered areas in full sunshine where you can protect them from cold temperatures and wind.
- Pumpkins that can withstand colder temperatures. Normally rain is not an issue in these areas.
How can I cook squash?
Squash soup has to be one of my faves! Bake the squash first, remove the seeds and then while it is cooking, fry some onions and garlic and herbs to taste. Add the cooked squash and a cup of water and whizz to a smooth consistency. For extra sweetness, add some squeezed orange juice.
Baked squash hash browns. Any leftover baked squash can be re-fried like potato cakes or hash browns. Add a few mushrooms and tomatoes and your vegan breakfast awaits!
- Storing seed. Do not store F1 crop seeds. These are genetically modified seeds, engineered to create reliable fruits of a standard size for one season but they will not necessarily produce seeds that result in the same crop the following year. If you choose organic seeds from the start, then these can be saved every year.
- Raise the fruit. If you decide to grow squash sprawling on the ground, you can use cut grass, flat stones or bricks to support the fruit as it grows. This also prevents slugs and snails from having a nibble as the soft fruit develops, and it keeps fungal rot in the soil, not on your fruit. If there is heavy rainfall, make sure your fruit is snugly supported higher off the ground and not lying directly on the soil.
- Harvesting seeds. To do this, cut open your squash and carefully pick out any full seeds that have not been cut. Choose plump ones with no obvious damage and make sure they are the biggest in the group. You can cook the squash now too!
- Place the seeds to dry on a recycled paper envelope (or tissue paper). When they go brown and dry, then store them in paper envelopes in a shady or dark place until you plant them the following April or May.
In conclusion, it is certainly possible to grow squash vertically if space is tight in your gardening space. Balcony squashes provide beautiful orange flowers as well as food! If grown on the ground, these are the sprawlers so give each plant lots of space. Hopefully, come the autumn you will be sipping sweet butternut squash soup.