Almost everyone has a favorite vegetable crop they look forward to harvesting from the garden. For some, its new potatoes and peas. For others, it’s that first batch of sweet corn.
That anticipation can sometimes get us in a little bit of trouble. Instead of waiting until soils are suitable for planting or temperatures have moderated, we try to speed up the process. For those who love tomatoes, the desire to get a crop as early as possible results in setting out plants earlier than is recommended with the hope they’ll survive and do well. It can work, but there may be better options.
Any tomato grower knows that tomatoes can be a little particular about planting conditions. Two of their requirements are an acceptable soil temperature for root growth and an acceptable air temperature for both plant growth and fruit set. If done correctly, both can be altered slightly to speed up the fruit harvest time frame.
From a root growth standpoint, remember that tomatoes prefer soil temperatures in the mid fifties and above. Monitor temperatures with a soil thermometer to a depth of two and a half inches below the surface. For best results check temperatures late morning. Can’t be there at that time to do so? Check before you leave in the morning and after you get home at night—averaging the two. If you want to try to speed up the warming process, consider the use of plastic mulch. It may take a few days of sunlight collection to warm it much, but in time, you can speed the rise in soil temperature faster than if soil is left bare. If you are planning to fertilize or add any irrigation, make sure you do so before installing the mulch.
Air temperature regulation is a little more difficult, with frost protection being the biggest hurdle. To help, consider the use of hot caps or water teepees. When placed over young plants, they provide frost protection while increasing the average temperature around the plant, encouraging growth. Protection will last as long as they adequately cover the plants, but air temperature damage doesn’t always end there. As plants grow and start to develop flowers, you may still not get fruit set. This is often the case when daytime temperatures are higher and the plants are growing, but night time temperatures remain in the mid-50s or below. When this occurs, the blossom will either not set fruit or fruit that is set may be misshapen.
How much time will these practices gain you? In all, you might gain a couple of weeks. For some, having the earliest tomatoes will be worth it. For others, waiting another couple weeks is no big deal.
Not sure when you need to have plants out? Check out our K-State Research & Extension Vegetable Garden Planting Guide available from your District Office as well as online at https://www.bookstore.ksre.ksu.edu/pubs/MF315.pdf.