What is the best way to predict time series data?
You can find the seasonality in your data (if there exist) and by removing the seasonality, find the trend of tomato price and predict the future price using the seasonality data and trend data. If you are using python, you can find the seasonal library useful to apply this method to your data.

The advantage of this method to your method is you don't need to think over finding dependent features and any feature engineering.

Moreover, as you have mentioned in tags of your question, you can using RNN to predict the future value by as your data is time series and sequential intrinsically. You can find this article useful.